Pump having diagnostic system

ABSTRACT

Apparatus and method for supplying lubricant to a plurality of lubrication sites. Embodiments include a pump with venting and non-venting piston return, a pump with stirrer and direct feed mechanism, a pump with CAN system and self-diagnostics, a pump with heated housing and reservoir and a pump with stepper motor and overdrive control.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Nonprovisional patentapplication Ser. No. 13/271,851 filed Oct. 12, 2011, which claims thebenefit of U.S. Provisional Patent Application 61/417,606 filed Nov. 29,2010, entitled, “Apparatus and Method for Supplying Lubricant”, and U.S.Provisional Patent Application 61/533,530, filed Sep. 12, 2011,entitled, “Apparatus and Method for Pumping Lubricant”, both of whichare incorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention generally relates to apparatus for supplyinglubricant, and more particularly to an automatic lubrication system forautomatically pumping lubricant to a plurality of lubrication sites.

BACKGROUND OF THE INVENTION

This invention has particular application to automatic lubricationsystems for supplying lubricant to multiple points of lubrication atpredetermined intervals and/or in predetermined amounts. LincolnIndustrial sells such automated systems under the Quicklub®,Centro-Matic® and Helios® trademarks. The Quicklub® system includes areservoir for holding a supply of lubricant, a stirrer for stirring thelubricant, and an electric or pneumatic pump for pumping lubricant fromthe reservoir to one or more progressive metering (divider) valves eachof which operates to dispense lubricant to multiple points oflubrication. Reference may be made to U.S. Pat. No. 6,244,387,incorporated herein by reference, for further details regarding anexemplary Quicklub® system. The Centro-Matic® system is similar to aQuicklub® system except that lubricant from the pump is deliveredthrough a single supply line to injectors each operating to dispense ametered amount of lubricant to a single lubrication point. Reference maybe made to U.S. Pat. No. 6,705,432, incorporated herein by reference,for further details regarding an exemplary Centro-Matic® system. TheHelios® system is a dual line system.

Although these systems have been proven to be reliable and commerciallysuccessful, there is a need for an improved pump unit which can be usedwith a wide variety of lubricant distribution systems and which is ofsimplified design.

SUMMARY OF THE INVENTION

In one aspect the present invention is directed to an apparatus forsupplying lubricant. The apparatus includes a reservoir having aninterior for holding lubricant. The apparatus also includes a pump forpumping lubricant from the reservoir to a lubricant distribution system.The pump includes a cylinder having a cylinder bore. The pump alsoincludes a cylinder inlet in communication with the interior of thereservoir for flow of lubricant from the reservoir into the cylinderbore. The pump further includes a cylinder outlet. The pump alsoincludes a piston movable in the cylinder bore. The pump furtherincludes a check valve in the cylinder bore between the piston and thecylinder outlet for blocking backflow through the outlet. The pump alsoincludes a vent passage communicating with the cylinder bore at alocation upstream from the check valve for venting the lubricantdistribution system. The pump further includes a linear position drivemechanism for moving the piston in a forward direction in the cylinderbore through a pumping stroke for pumping lubricant through the cylinderoutlet to the lubricant distribution system, in a rearward directionthrough a non-venting return stroke in which the vent passage does notcommunicate with the interior of the reservoir, and in a rearwarddirection through a venting return stroke in which the vent passagecommunicates with the interior of the reservoir. The apparatus furtherincludes a controller for calibrating and controlling the operation ofthe linear position drive mechanism.

In another aspect, the present invention includes a method of supplyinglubricant to a vented lubricant distribution system and to a non-ventedlubricant distribution system that includes operating a linear positiondrive mechanism to move a piston in a cylinder bore through a pumpingstroke to pump lubricant through an outlet of the cylinder bore to thevented lubricant distribution system and/or to the non-vented lubricantdistribution system. The method also includes operating the linearposition drive mechanism to move the piston through a non-venting returnstroke having a first length during which the non-vented lubricantdistribution system is not vented. The method further includescalibrating the linear position drive mechanism and operating thecalibrated linear position drive mechanism to move the piston through aventing return stroke having a second length different from the firstlength during which the vented lubricant distribution system is vented.

In one aspect the present invention is directed to an apparatus forpumping lubricant that includes a reservoir having an interior forholding lubricant. The apparatus also includes a stirrer rotatable inthe reservoir. One advantage of the stirrer includes maintaining thelubricant at a viscosity sufficiently low that the lubricant more easilyflows. In colder environmental conditions, the lubricant may becomestiff or thick. The stirrer fluidizes the lubricant which allows thelubricant pump to operate more efficiently. The apparatus furtherincludes a force-feed mechanism on the stirrer operable on rotation ofthe stirrer to exert a pushing force pushing lubricant from thereservoir along a defined flow path. The apparatus also includes a pumpbelow the reservoir for pumping lubricant from the reservoir to thelubricant distribution system. The pump includes a cylinder having acylinder bore and a piston movable in the cylinder bore through apumping stroke and a return stroke. The cylinder bore communicates withthe interior of the reservoir via said defined flow path wherebyrotation of the stirrer causes the force-feed mechanism on the stirrerto exert the pushing force pushing lubricant along the defined flowpath, and such that movement of the piston through said return strokegenerates a reduced pressure in the cylinder bore to exert a pullingforce pulling lubricant along the defined flow path, the pushing andpulling forces combining to move lubricant along the defined flow pathfrom the reservoir into the cylinder bore.

In another aspect, the present invention includes a method of pumpinglubricant from a reservoir which includes rotating a stirrer in thereservoir to cause a force-feed mechanism on the stirrer to exert apushing force pushing lubricant along a defined flow path from thereservoir to a cylinder bore. The method also includes moving a pistonin the cylinder bore through a pumping stroke. The method furtherincludes moving the piston through a return stroke to generate a reducedpressure in the cylinder bore. The reduced pressure exerts a pullingforce pulling lubricant along the defined flow path. The pushing andpulling forces combine to move lubricant along the defined flow pathinto the cylinder bore.

In one aspect the present invention is directed to a system forsupplying lubricant which includes a reservoir for holding lubricant.The reservoir has a reservoir outlet. The system also includes a pumpcomprising a cylinder defining a cylinder bore, a cylinder inlet incommunication with the reservoir outlet for flow of lubricant from thereservoir into the cylinder bore, a cylinder outlet, and a pistonmovable in the cylinder bore. The system further includes a lubricantdelivery system in communication with the cylinder outlet for deliveringlubricant. The system further includes a drive mechanism comprising astepper motor for reciprocating the piston in the cylinder bore. Thesystem also includes a sensor for sensing a condition of the system andproviding a condition signal. The system also includes an alarm. Thesystem further includes a controller for controlling the operation ofthe motor by selectively energizing the motor to reciprocate the piston.The controller is responsive to the condition signal to modify systemoperation such as by selectively energizing the alarm when the conditionsignal is outside a preset range.

In another aspect, the present invention includes a system for supplyinglubricant which includes a reservoir for holding lubricant. Thereservoir has a reservoir outlet. The system also comprises a pumpincluding a cylinder defining a cylinder bore, a cylinder inlet incommunication with the reservoir outlet for flow of lubricant from thereservoir into the cylinder bore, a cylinder outlet, and a pistonmovable in the cylinder bore. The system also includes a lubricantdelivery system in communication with the cylinder outlet for deliveringlubricant. The system further includes a drive mechanism including amotor for reciprocating the piston in the cylinder bore. The system alsoincludes a sensor for sensing a condition of the system and providing acondition signal. The system further includes an alarm. The system alsoincludes a controller for controlling the operation of the motor byselectively energizing the motor to reciprocate the piston. Thecontroller is responsive to the condition signal to modify systemoperation such as by selectively energizing the alarm when the conditionsignal is outside a preset range. The sensor comprises at least one ormore of the following: a pressure sensor monitoring a lubricant pressureof the lubricant delivery system, wherein the condition signal is apressure signal and wherein the controller is responsive to the pressuresignal to energize the alarm when the pressure signal indicates that thelubricant pressure is less than a minimum pressure; a pressure sensormonitoring a lubricant pressure at the pump, wherein the conditionsignal is a pressure signal and wherein the controller is responsive tothe pressure signal to energize the alarm when the pressure signalindicates that the lubricant pressure at the pump is greater than amaximum pressure; a motion sensor monitoring a movement of the piston,wherein the condition signal is a motion signal and wherein thecontroller is responsive to the motion signal to energize the alarm whenthe motion signal indicates that the piston movement is less than aminimum movement; a level sensor monitoring a lubricant level of thereservoir, wherein the condition signal is a level signal and whereinthe controller is responsive to the level signal to energize the alarmwhen the level signal indicates that the lubricant level is less than aminimum level; and a pressure sensor monitoring a lubricant pressure ofthe lubricant delivery system, wherein the condition signal is apressure signal and wherein the controller is responsive to the pressuresignal to energize the alarm when the pressure signal indicates that thelubricant pressure is less than a minimum pressure after a given periodof time of motor pump operation has elapsed.

In yet another aspect, the present invention includes a system forsupplying lubricant which includes a reservoir for holding lubricant.The reservoir has a reservoir outlet. The system also includes a pumpincluding a cylinder defining a cylinder bore, a cylinder inlet incommunication with the reservoir outlet for flow of lubricant from thereservoir into the cylinder bore, a cylinder outlet, and a pistonmovable in the cylinder bore. The system further includes a lubricantdelivery system that is in communication with the cylinder outlet andhas a plurality of valves, each for delivering lubricant. The systemalso includes a drive mechanism including a motor for reciprocating thepiston in the cylinder bore. The system also includes a controller forcontrolling the operation of the motor by selectively energizing themotor to reciprocate the piston. The system also includes a controllerarea network (CAN) bus connected to the controller. The system alsoincludes a power supply. The system further includes a power busconnected to the power supply. The system also includes a plurality ofactuators, each associated with one of the valves for opening andclosing its associated valve. The system further includes a plurality ofCAN relays, each connected to the power bus and connected to one or moreactuators for selectively energizing its connected actuators to open andclose the valves associated with the actuators in order to deliverlubricant. The system also includes a plurality of CAN modules, eachassociated with and controlling one or more of the CAN relays. Each CANmodule is connected between the CAN bus and its CAN relay forcontrolling its relay in response to instructions provided by thecontroller via the CAN bus.

In one aspect the present invention is directed to apparatus forsupplying lubricant. The apparatus comprises a reservoir including atank for holding lubricant. The reservoir includes an outlet forreleasing lubricant from the reservoir. The apparatus also comprises apump assembly including a housing having a thermally conductive top wallon which the reservoir mounts. The top wall includes an upper facefacing the reservoir and a lower face opposite the upper face. The pumpassembly also includes a lubricant pump mounted in the housing forpumping lubricant from the tank through the reservoir outlet and to alubrication site. The pump includes an inlet in fluid communication withthe reservoir outlet. The assembly also includes a heater mounted insidethe housing in direct thermal contact with the top wall of the housingfor heating lubricant held in the tank of the reservoir before passingthrough the reservoir outlet.

In one aspect the present invention is directed to an apparatus forsupplying lubricant which includes a reservoir for holding lubricant.The reservoir has a reservoir outlet. The apparatus also includes a pumpthat includes a cylinder defining a cylinder bore, a cylinder inlet incommunication with said reservoir outlet for flow of lubricant from thereservoir into the cylinder bore, a cylinder outlet, and a pistonmovable in the cylinder bore. The apparatus also includes a drivemechanism including a motor for driving the pump, such as a steppermotor for reciprocating the piston in the cylinder bore. The steppermotor has a continuous duty operating range. The apparatus furtherincludes a controller for controlling the operation of the stepper motorby selectively applying pulse width modulated (PWM) pulses to thestepper motor to control a speed and a torque of the motor. Theapparatus also includes a pressure sensor for sensing the pressure ofthe supplied lubricant and providing a pressure signal indicative of thepressure at the outlet. The controller is responsive to the pressuresignal to selectively apply the PWM pulses to the stepper motor to varythe speed and the torque of the stepper motor as a function of thepressure signal by applying PWM pulses having a power within thecontinuous duty operating range of the stepper motor. The controller isalso responsive to the pressure signal to selectively apply the PWMpulses to the stepper motor to vary the speed and torque of the steppermotor as a function of the pressure signal by applying overdrive PWMpulses for a period of time. The overdrive PWM pulses have an overdrivepower greater than the continuous duty operating range of the steppermotor.

In another aspect, the present invention includes an apparatus forsupplying lubricant which includes a reservoir for holding lubricant.The reservoir has a reservoir outlet. The apparatus also includes a pumpincluding a cylinder defining a cylinder bore, a cylinder inlet incommunication with said reservoir outlet for flow of lubricant from thereservoir into the cylinder bore, a cylinder outlet, and a pistonmovable in the cylinder bore. The apparatus also includes a drivemechanism including a stepper motor for reciprocating the piston in thecylinder bore. The apparatus further includes a controller forcontrolling the operation of the stepper motor by selectively applyingPWM pulses to the stepper motor to control a speed and a torque of themotor The controller includes a memory storing a speed vs. pressureprofile of the stepper motor. The apparatus also includes a pressuresensor for sensing the pressure at the outlet of the cylinder bore andproviding a pressure signal indicative of the pressure at the outlet.The controller is responsive to the pressure signal to selectively applythe PWM pulses to the stepper motor to vary the speed and the torque ofthe stepper motor as a function of the pressure signal and as a functionof the profile by applying PWM pulses having a power within thecontinuous duty operating range of the stepper motor.

The above summary is provided to introduce a selection of concepts insimplified form that are further described below in the DetailedDescription. The summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter. Other objects and features will be in part apparent and in partpointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a conventional automated lubricationsystem including divider valves for directing lubricant to points oflubrication;

FIG. 2 is a diagrammatic view of a conventional automated lubricationsystem including injectors for directing lubricant to points oflubrication;

FIG. 3 is a perspective of a first embodiment of a pump unit of thisinvention;

FIG. 4 is a bottom plan of the pump unit of FIG. 3;

FIG. 5 is a vertical section of the pump unit of FIG. 3;

FIG. 6 is an enlarged portion of FIG. 5 illustrating a linear drivemechanism of the pump unit;

FIG. 7 is a vertical section of the linear drive mechanism of taken inthe plane of 7-7 of FIG. 6;

FIG. 8 is an enlarged section of the linear drive mechanism showing acalibration mechanism;

FIG. 9 is a FIG. 8 is an enlarged section of the linear drive mechanismshowing a piston at a limit of a return stroke;

FIG. 10 is a diagrammatic view of a lubrication system of the presentinvention including a divider valve distribution system;

FIG. 11 is a diagrammatic view of a lubrication system of the presentinvention including an injector distribution system;

FIG. 12 is a diagrammatic view of a lubrication system of the presentinvention including a zoned CAN bus distribution system;

FIG. 13 is a perspective of a valve body and a plurality ofelectronically controlled valves used in the CAN bus lubricationdistribution system of FIG. 12;

FIG. 14 is a vertical section of the valve body and electronicallycontrolled valves of FIG. 13;

FIG. 15 is a vertical section similar to FIG. 14 but rotated 90 degrees;

FIG. 16 is a diagrammatic view of a zoned lubrication system of thepresent invention, each zone including a divider valve distributionsystem;

FIG. 17 is a diagrammatic view of a zoned lubrication system of thepresent invention, one zone including a CAN bus lubrication distributionsystem and another zone including a divider valve distribution system;

FIG. 18 is a diagrammatic view of a zoned lubrication system of thepresent invention, each zone including an injector distribution system;

FIG. 19 is a diagrammatic view of a zoned lubrication system of thepresent invention, one zone including a CAN bus lubrication distributionsystem and another zone including an injector distribution system;

FIG. 19A is a diagrammatic view of a multiple zone lubrication system ofthe present invention, one zone including a single line, injectordistribution system and another zone including a dual-line injectordistribution system;

FIG. 19B is a diagrammatic view of a multiple zone lubrication system ofthe present invention, one zone including a single line, divider valvedistribution system and another zone including a dual-line injectordistribution system;

FIG. 19C is a diagrammatic view of a single zone lubrication system ofthe present invention, including a dual-line injector distributionsystem;

FIG. 20 is a schematic view of a first alternative drive mechanism for apumping unit;

FIG. 21 is a schematic view of a second alternative drive mechanism fora pumping unit;

FIG. 22 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having a closed loop, injector system with aninternal pressure transducer;

FIG. 23 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a ventmeter testfor a lubrication system having a closed loop, injector system with aninternal pressure transducer;

FIG. 24 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a maximum pressuretest for a lubrication system having a closed loop, injector system withan internal pressure transducer or an open loop, non-injector system(e.g., a divider valve distribution system) with an internal pressuretransducer;

FIG. 25 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide full stroke test ofa piston for a lubrication system having a closed loop, injector systemwith an internal pressure transducer or an open loop, non-injectorsystem with an internal pressure transducer;

FIG. 26 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide reservoir leveltest for a lubrication system having a closed loop, injector system oran open loop, non-injector system, each with or without an internalpressure transducer;

FIG. 27 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a cycle (i.e.,injector reset) time out test for a lubrication system having a closedloop, injector system with an internal pressure transducer or an openloop, non-injector system with an internal pressure transducer;

FIG. 28 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a lubricantreservoir stiffness test for a lubrication system having a closed loop,injector system with an internal pressure transducer or an open loop,non-injector system with an internal pressure transducer;

FIG. 29 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having an open loop, non-injector system withan internal pressure transducer;

FIG. 30 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having a closed loop, injector system withoutan internal pressure transducer;

FIG. 31 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a ventmeter testfor a lubrication system having a closed loop, injector system withoutan internal pressure transducer;

FIG. 32 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a maximum pressuretest for a lubrication system having a closed loop, injector systemwithout an internal pressure transducer or an open loop, non-injectorsystem without an internal pressure transducer;

FIG. 33 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide full stroke test ofa piston for a lubrication system having a closed loop, injector systemwithout an internal pressure transducer, or an open loop, non-injectorsystem without an internal pressure transducer;

FIG. 34 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a cycle (i.e.,injector reset) time out test for a lubrication system having a closedloop, injector system without an internal pressure transducer, or anopen loop, non-injector system without an internal pressure transducer;

FIG. 35 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a lubricantreservoir stiffness test for a lubrication system having a closed loop,injector system without an internal pressure transducer, or an openloop, non-injector system without an internal pressure transducer;

FIG. 36 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having an open loop, non-injector systemwithout an internal pressure transducer;

FIG. 36A is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a CAN bus lubrication system having actuator valves without aninternal pressure transducer such as illustrated in FIG. 19;

FIG. 37 is a block diagram of one embodiment of a CAN bus lubricationsystem 2300 of the invention for supplying lubricant including multiplezones of actuator valves;

FIG. 37A is a block diagram of another embodiment of a CAN buslubrication system 2300 of the invention for supplying lubricantincluding a zone of divider valves and a zone of injectors;

FIG. 38 is a perspective of another embodiment of a pump unit of thisinvention;

FIG. 39 is a vertical section taken through the pump unit of FIG. 38illustrating a refill port for refilling a reservoir of the unit;

FIG. 40 is an enlarged portion of FIG. 39;

FIG. 41 is a vertical section taken through the pump unit of FIG. 38illustrating a linear drive mechanism of the pump unit;

FIG. 42 is an enlarged portion of FIG. 39 illustrating the linear drivemechanism;

FIG. 43 is an enlarged portion of FIG. 41 showing a cylinder inlet ofthe drive mechanism;

FIG. 44 is a view similar to FIG. 42 but rotated 90 degrees toillustrate an oblong portion of the cylinder inlet;

FIG. 45 is a plan of a stirring mechanism of the pump unit;

FIG. 46 is a vertical section taken through the drive motor and relatedcomponents of the stirrer;

FIG. 47 is an enlarged vertical section taken in the plane of 47-47 ofFIG. 45, illustrating a force-feed mechanism on the stirrer;

FIG. 48 is a graph comparing the results of tests conducted using astate-of-the art pump and a pump unit of this invention;

FIG. 49 is a bottom plan of the pump unit of FIG. 38;

FIG. 50 is an enlarged vertical section taken in the plane of 50-50 ofFIG. 49;

FIG. 51 is an enlarged vertical section showing components of the lineardrive mechanism, including a drive screw, piston, follower housing, andfollower;

FIG. 52 is a perspective of the drive screw;

FIG. 53 is a sectional view of the follower;

FIG. 54 is a vertical section taken in the plane of 54-54 of FIG. 42;

FIG. 55A is a bottom plan of a pump unit having a temperature sensor andheater;

FIG. 55B is a fragmentary cross section of the pump unit taken in theplane of 55B-55B of FIG. 55A;

FIG. 55C is perspective of a pump unit having a reservoir separated;

FIG. 55D is a fragmentary cross section of the pump unit taken in theplane of 55D-55D of FIG. 55A;

FIG. 55E is a fragmentary cross section of an alternate embodiment of apump unit taken in the plane of 55B-55B of FIG. 55A;

FIG. 56 is a graph illustrating a curve of power over time of a steppermotor and illustrating the continuous duty operating range of thestepper motor;

FIG. 57 is a graph illustrating speed in rpm vs. pressure in psi of anoperating profile of a stepper motor of the invention and of a stallcurve of the stepper motor; and

FIG. 58 is a graph illustrating pressure in psi vs. speed in rpm of astall curve of the stepper motor.

Corresponding parts are indicated by corresponding reference numbersthroughout the drawings.

DETAILED DESCRIPTION

FIG. 1 illustrates a conventional Quicklub® system, generally designated100, comprising a pump unit 110 that operates to pump lubricant througha lube supply line 114 to a master divider valve, generally designatedby 118, having an inlet 120 and multiple outlets 124 connected via lines128 to the inlets 130 of additional (slave) divider valves, generallydesignated by 134. The divider valves 134 are connected via lines 138 tobearings 144 or other points of lubrication. The number of dividervalves 134 used will vary depending on the number of lubrication pointsto be serviced.

The pump unit 110 includes a reservoir 150 for holding a lubricant(e.g., grease), a stirrer 156 for stirring the lubricant in thereservoir, and an expansible chamber pump 158 in a pump housing 160below the reservoir. A motor 164 in the pump housing rotates the stirrer156 to stir lubricant in the reservoir. The motor also 164 rotates aneccentric mechanism 170 to move a spring-biased piston through a seriesof pumping strokes to pump lubricant through the supply line 114 to thedivider valve(s) 118, 134. The mechanism for driving the stirrer 156 andthe eccentric mechanism 170 includes a relatively bulky drive train 180comprising several gears. The pump unit 110 includes a programmablecontroller for controlling operation of the motor 164 and for receivingsignals from a proximity switch 186 monitoring the operation of themaster divider valve 118.

FIG. 2 illustrates a conventional Centro-Matic® system, generallydesignated 200, comprising a pump unit 210 that operates to pumplubricant through a lube supply line 214 to a plurality of injectors130, each of which has an inlet communicating with the lube supply line214 via passages in a manifold 132 and an outlet 138 connected via aline 144 to a bearing 155 or other point of lubrication. The pump unit210 is similar to the pump unit 110 described above.

FIGS. 3-9 illustrate apparatus of the present invention comprising apump unit 300 for supplying lubricant to different types of lubricantdistribution systems (e.g., progressive systems, injector systems, CANbus systems, dual line systems and combinations thereof). In general,the pump unit 300 comprises a reservoir, generally designated by 304,for holding a supply of lubricant (e.g., grease) and a pump housing 306below the reservoir for housing various pump components of the unit, aswill be described. The pump housing 306 includes a pair of mountingflanges 308 (FIG. 3) for mounting the pumping unit in an uprightposition on a suitable structure.

In the embodiment of FIG. 3, the reservoir 304 comprises a cylindricalside wall 310, an open top 312 for loading lubricant into the reservoir,a bottom wall 314, and an outlet 316 in the bottom wall for discharginglubricant from the reservoir. A stirrer, generally designated by 320, isprovided for stirring lubricant in the reservoir. The stirrer 320comprises a rotary hub 322 rotatable about a vertical axis by a firstdrive mechanism 326 (FIG. 4) in the pump housing 306, an arm 328extending laterally outward from the hub across the bottom wall 314, anda wiper 330 on the arm. The wiper 330 has a lower blade portion 330 aangling down toward the bottom wall 314 and an upper portion 330 bextending up alongside the side wall 310 of the reservoir. Rotation ofthe stirrer fluidizes lubricant in the reservoir. The lower bladeportion 330 a of the wiper 330 also forces lubricant down through theoutlet 316 of the reservoir.

Referring to FIG. 4, a temperature sensor 332 is mounted inside the pumphousing 306 immediately adjacent the bottom wall 314 of the reservoir304 for sensing the temperature bottom wall and thus the temperature ofthe lubricant in the reservoir.

Referring to FIGS. 5 and 6, a pump cylinder, generally designated by334, is mounted in the pump housing immediately adjacent the bottom wall314 of the reservoir 304. In the illustrated embodiment, the pumpcylinder 334 is of two-part construction, comprising a first inlet part334 a and a second outlet part 334 b in threaded engagement with theinlet part. The two parts have longitudinal bores that combine to definea central longitudinal cylinder bore 338. The inlet cylinder part 334 ahas a radial bore 340 defining a cylinder inlet in communication withthe reservoir outlet 316 for flow of lubricant from the reservoir 304directly (i.e., along a defined flow path) into the longitudinalcylinder bore 338. A ball check valve 344 is mounted in the outletcylinder part 334 b for movement between a closed position in which itengages a valve seat 348 on the outlet cylinder part to block flowthrough the longitudinal cylinder bore 338 and an open position in whichit allows flow through the bore. A coil compression spring 352 reactingat one end against the ball valve urges the ball valve toward its closedposition. The opposite end of the spring reacts against an outletfitting 354 threaded into the outlet end of the cylinder bore 338. Theoutlet fitting has a lube outlet port 356 defining a cylinder outlet anda pressure sensor port 358.

As shown in FIG. 4, a T-fitting 360 is connected to the lube outlet port356 of the outlet fitting 354 for flow of fluid to a first feed line 364attached to the pump housing 306 at one location and to a second feedline 366 attached to the pump housing at a second location spaced aroundthe housing from the first location. The outlet end of each feed line364, 366 is equipped with a quick connect/disconnect connector 370 tofacilitate connection of the feed line to a lube supply line supplyinglubricant to a distribution system of one kind or another. In general,only one of the two feed lines 364, 366 is used for any givendistribution system, the feed line selected for use being the mostsuitable configuration for conditions in the field.

A pressure sensor 372 is attached to the pressure sensor port 358 of theoutlet fitting 354. The pressure sensor senses the pressure at theoutlet end of the cylinder bore 338 (FIG. 6).

As further illustrated in FIG. 6, a vent passage 376 in the pumpcylinder 334 provides fluid communication between a first location inthe longitudinal cylinder bore 338 upstream from the check valve seat348 and a second location in the longitudinal cylinder bore downstreamfrom the check valve seat. The downstream end of the vent passage 376communicates with the second location via a radial bore 380 in theoutlet cylinder part 334 a. The purpose of this vent passage 376 willbecome apparent hereinafter.

The pump unit 300 further comprises a piston 384 movable in areciprocating manner in the cylinder bore 338 by a second drivemechanism, generally designated 390. In the embodiment of FIGS. 3-9, thedrive mechanism 390 is a linear position drive mechanism comprising astepper motor 394 having an output shaft 396 rotatable in a bushing 398in an end wall 400 of a follower housing 404 secured to the bottom wallof the reservoir. The shaft 396 is in driving engagement with a leadscrew 410, and the lead screw is in threaded engagement with a follower414 in the follower housing 404. The follower 414 and piston 384 areattached in a non-rotatable manner. Desirably, the follower and pistonare integrally formed as one piece, but they may be formed as separatepieces non-rotatably affixed to one another. As illustrated in FIG. 7,the follower 414 has a radial collar 418 with notches 420 for receivingstationary linear guides 424 on the inside of the follower housing 404.The guides 424 extend in a direction generally parallel to thelongitudinal cylinder bore 338 and hold the follower 414 (and piston384) against rotation as the lead screw 410 is rotated by the steppermotor 394. As a result, rotation of the motor output shaft 396 in onedirection causes the piston 384 to move in the cylinder bore 338 througha pumping (power) stroke and rotation of the shaft 396 in the oppositedirection causes the piston to move in the cylinder bore through areturn stroke. The lengths of the strokes are controlled by operation ofthe stepper motor.

A calibration mechanism, generally designated 430 in FIG. 8 is providedfor calibrating operation of the stepper motor 394 relative to theposition of the piston 384 in the cylinder bore 338. In the illustratedembodiment, this mechanism 430 comprises a magnet 434 on the follower414 movable with the piston and follower, and at least one and desirablytwo magnetic field sensors 440, 442 mounted on the follower housing 404at spaced-apart locations with respect to the direction of pistonmovement. By way of example only, the sensors 440, 442 may be Reedswitches which are in proximity to the magnet 434.

In some embodiments, one motor may be used to drive the pump and drivethe stirrer. In other embodiments, the stirrer motor 326 and the steppermotor 394 are separate, distinct, independently energized motors ratherthan one motor for both the stirrer and the pump. One advantage of usingtwo motors is as follows. In colder environments, the lubricant maybecome stiff resulting in an increased resistance to rotation of thestirrer. This increased resistance slows down rotation of the motordriving the stirrer. If the motor driving the stirrer is also drivingthe pump, the slower rotation reduces the rate of operation of the pumpand the rate at which lubricant is pumped. In contrast, when twoindependently energized motors are used, if the lubricant is stiff andslows down the rotation of the stirrer motor, the pump motor cancontinue to operate independently to pump lubricant at a speedindependent of the speed of the stirrer motor.

Referring to FIGS. 10-12, the pump unit 300 includes a controller 450for calibrating and controlling the operation of the linear positiondrive mechanism 390. The controller 450 receives signals from thepressure sensor 372 and the calibration mechanism 430 (e.g., magneticfield sensors 440, 442). The controller 450 includes a programmablemicroprocessor that processes information and controls operation of thestirrer motor 326 and the stepper motor 394. An operator input 454 witha display 456 is provided for inputting information to the controllerand for use by the controller to present information to an operator.This information may include the type of lubrication distribution systemto be used with the pumping unit, the volume of lubricant to bedelivered to each point of lubrication (e.g., bearing), and thefrequency of lubrication events. Information can also be uploaded anddownloaded to and from the controller via a USB port 460 on the pumphousing of the pump unit.

Power is supplied to the pump unit 300 via a power supply 462 which istypically the power supply of the equipment being lubricated.

As noted previously, the pump unit 300 of this invention can be usedwith different distribution systems. By way of example but notlimitation, the pump unit may be used with a progressive (divider) valvedistribution system 500 as shown FIG. 10, an injector distributionsystem 600 as shown in FIG. 11, a CAN bus distribution system 700 asshown in FIG. 12, dual-line systems as shown in FIGS. 19A-19C, zoneddistribution systems as shown in FIGS. 16-19, and combinations of thesesystems. Examples of these systems are described below.

In the progressive distribution system 500 of FIG. 10, the pump unit 300pumps the desired amount of lubricant through a lube supply line 510 toa series of conventional divider valves 530 at desired intervals oftime. The divider valves operate to deliver metered amounts of lubricantto respective points of lubrication 550 (e.g., bearings). Each dividervalve has a proximity switch 532 connected to the controller 450 formonitoring proper operation of the divider valve. The controller 450 issuitably programmed (e.g., via the operator input 454 and/or USB port460) to operate the pump unit 300 as follows.

Desirably, the controller 450 initiates operation of the stirrer motor326 before the stepper motor 394 is operated to reciprocate the piston384. This sequence allows the stirrer 320 to fluidize the lubricant andprime the pump cylinder 334 with lubricant before the actual pumping oflubricant begins, which can be especially advantageous if the lubricantis in a viscous condition, as in cold-temperature environments. After asuitable delay of predetermined length (e.g., eight-twelve seconds), thestepper motor 394 is energized to move the piston 384 through asuccession of pumping (power) strokes and return strokes to pump thedesired amount of lubricant through the feed line (364 or 366) connectedto the distribution lube supply line 510. When the pump unit is operatedin this mode, the downstream end of the piston 384 remains downstreamfrom the location at which the vent passage 376 communicates with thecylinder bore 338 (see FIG. 8 showing the piston at the limit of itsreturn stroke). As a result, there is no venting of the lube supply line510 of the distribution system 500 to the reservoir 304 of the pump unitduring the return strokes of the piston 384. Such venting is unnecessaryin a progressive (divider) valve distribution application. A pistonreturn stroke in which venting does not occur is hereinafter referred toas a “non-venting” return stroke.

In the injector distribution system 600 of FIG. 11, the controller 450of the pump unit 300 is programmed to operate the unit to pump thedesired amount of lubricant through a lube supply line 610 to aplurality of injectors 620 at desired intervals of time. The injectorsoperate to deliver metered amounts of lubricant to respective points oflubrication 630 (e.g., bearings). In this mode, the pump unit 300operates as described above except that during its return stroke thepiston 384 moves to a vent position upstream from the location at whichthe vent passage 376 communicates with the cylinder bore 338 (see FIG. 9showing the piston at the limit of its return stroke). As a result,lubricant is vented to the reservoir 304 during the return strokes ofthe piston to allow the injectors 620 to reset for successive cycles ofoperation. A piston return stroke in which venting occurs is hereinafterreferred to as a “venting” return stroke.

In the CAN bus and divider valve distribution system 700 of FIG. 12, thecontroller 450 of the pump unit 300 is programmed to operate the unit topump the desired amount of lubricant through a lube supply line 702 to afirst valve body comprising a manifold 706 having outlets 710 connectedto respective points of lubrication 714 (e.g., bearings) in a first zoneZ1. The flow of fluid through the bores is controlled by respectiveelectronically controlled valves 718 receiving control signals from thecontroller 450 and receiving power to energize the valves via a powerfield bus 720. In the embodiment of FIG. 12, lubricant is also deliveredby the lube supply line 710 to a second valve body comprising a manifold724 fluidly connected in series with the first manifold 706. Themanifold 724 has outlets 728 connected to respective points oflubrication 730 (e.g., bearings) in a second zone Z2. The flow of fluidthrough the manifold to the outlets 728 is controlled by respectiveelectronically controlled valves 730 receiving control signals from thecontroller 450 and receiving power to energize the valves via the powerfield bus 720.

FIGS. 13-15 illustrate an exemplary valve body (manifold 706) and aplurality of exemplary electronically controlled valves (valves 718)used in the CAN bus lubrication distribution system of FIG. 12. Themanifold 706 is equipped with four such valves, but this number may varyfrom one to two or more. The manifold 706 comprises a block having aninlet 732 connected to the lube supply line 702, a supply passage 734extending from the inlet through the manifold, and a plurality of outletpassages 738 connecting the supply passage and respective outlets 710 ofthe manifold. Ball check valves 742 in the outlets 710 are biased towardtheir closed positions by springs to prevent backflow.

Each valve 718 comprises a valve member 746 (e.g., a movable plunger asshown in FIG. 15) associated with a respective outlet 710 of themanifold 706 for controlling fluid flow through the outlet. The valvemember is moved between its open and closed positions by anelectronically controlled actuator 750, which in this embodimentincludes a solenoid 752. The actuator 750 also includes an electroniccontrol circuit (ECC) 756 (e.g., a microcontroller circuit) forcontrolling the operation of the actuator. Each ECC is part of the CANnetwork connected to the controller 450 of the pump unit 300 andresponds to CAN messages from the controller that are addressed to theparticular ECC 756. The ECC has a control port 758 adapted to receivethe CAN messages for operating the actuator 750 to move the valve member746 between its open and closed positions. The actuator 750 has a powerport 762 for receiving power for selectively energizing the solenoid752. In one embodiment, the actuator 750 includes a switch 768 (FIG. 15)controlled by the ECC and connected to the power wires. The switch 768is selectively closed by the ECC 756 to connect the external powersupply via the power wires to the solenoid 752 (or other device) whichmoves the valve member 746 to permit fluid flow.

As shown in FIG. 13, the power field bus 720 is daisy-chained from onevalve 718 to another valve 718 via suitable electrical connectors 770.If the ECC requires power, it may be connected to the external powersupply via the switch 768 and the power wires.

In one embodiment, the power field bus 720 comprises a four-wire buswith two wires carrying CAN messages from the communications port (COM772) of the controller 450 of the pumping unit 300 to the electronicallycontrolled circuit (ECC 756) for controlling the operation of theelectronically-operated valves 718, and two wires supplying power froman external power supply (e.g., supplying 24 volts) to a respectiveelectronically controlled actuator 750 for energizing a respectivesolenoid. The power wires may be connected to a power supply of theapparatus being lubricated, or the power wires may be connected to aseparate power supply. The controller 450 is programmable by anoperator, such as by the input device 454 (e.g., keypad, touch screen)and/or the USB port 460 to control the mode of operation. In the CAN busmode, the operator may program the controller 450 to control thesequence of operation of the valves 740, the frequency of valveoperation, and the amount of lubricant to be delivered.

The construction and operation of the second manifold 724 and itsassociated electronically controlled valves 730 (FIG. 12) issubstantially identical to the construction and operation of the firstmanifold 706 and associated valves 718 described above. The flow offluid through the passages in the second manifold 724 is controlled byrespective electronically-operated valves receiving control signals fromthe controller and power to energize the solenoids 752 via the powerfield bus 720.

In general, the solenoid valves 718, 730 of the two manifolds 706, 724are operated by the controller 450 of the pump unit 300 in a desiredsequence, preferably one at a time, for delivering a metered amount offluid (determined by the stroke of the piston) to respective points oflubrication in the two different zones Z1, Z2. The piston 384 of thepump unit 300 is operated to move through non-venting return strokes, asdescribed above regarding the progressive distribution system 500.

In the distribution system 800 of FIG. 16, the controller is programmedto operate the pump unit 300 to pump the desired amount of lubricantthrough a lube supply line 804 to a manifold 808 having passages influid communication with two outlets 816. The flow of fluid through thepassages to respective outlets is controlled by respectiveelectronically-operated valves 818 receiving control signals from thecontroller 450 of the pump unit 300 via a power field bus 820. One ofthe two outlets 816 is connected by a lube supply line 824 to a firstseries of one or more divider valves 830 for delivering metered amountsof lubricant to points of lubrication 834 (e.g., bearings) in a firstzone Z1. The other outlet 816 is connected by a lube supply line 840 toa second series of one or more divider valves 844 for delivering meteredamounts of lubricant to points of lubrication 850 (e.g., bearings) in asecond zone Z2. The master divider valve of each series of master valves830, 844 has a proximity switch 846 connected to the controller 450 formonitoring proper operation of the divider valve. Flow of lubricant tothe zones Z1, Z2 is controlled by selective activation of theelectronically-operated valves 818, as described in the previousembodiment (FIGS. 12-15). When used with this type of lubricationdistribution system, the piston 384 of the pump unit 300 moves throughnon-venting return strokes, as described above regarding the progressivedistribution system 500.

In the embodiment of FIG. 16, the manifold 808 is constructedessentially the same as described above regarding FIGS. 13-15.

In the distribution system 900 of FIG. 17, the controller 450 isprogrammed to operate the pump unit 300 to pump the desired amount oflubricant through a lube supply line 904 to a manifold 908 havingpassages in fluid communication with two outlets 916. The flow of fluidthrough the passages to respective outlets 916 is controlled byrespective solenoid-operated valves 918 receiving control signals fromthe controller 450 via a power field bus 920. One of the two outlets 816is connected by a lube supply line 924 to a first series of one or moredivider valves 930 for delivering metered amounts of lubricant to pointsof lubrication 934 (e.g., bearings) in a first zone Z1. The masterdivider valve of the series of divider valves 930 has a proximity switch932 connected to the controller 450 for monitoring proper operation ofthe divider valve. The other outlet 916 is connected by a lube supplyline 940 to a second manifold 944 having passages in fluid communicationwith outlets 946 connected to respective points of lubrication 948(e.g., bearings) in a second zone Z2. The flow of fluid through theoutlets 946 in the second manifold 944 is controlled by respectiveelectronically-operated valves 950 receiving control signals from thecontroller via the power field bus 920. Flow of lubricant to the firstand second zones Z1, Z2 is controlled by selective activation of theelectronically-operated valves 918, 950, as described in the embodimentof FIGS. 12-15. When used with this type of lubrication distributionsystem, the piston 384 of the pump unit 300 moves through non-ventingreturn strokes, as described above regarding the progressivedistribution system 500.

In the embodiment of FIG. 17, the manifold 808 is constructedessentially the same as described above regarding FIGS. 13-15.

In the distribution system 1000 of FIG. 18, the controller 450 of thepump unit 300 is programmed to operate the unit to pump the desiredamount of lubricant through a lube supply line 1004 to a manifold 1008having passages in fluid communication with two outlets 1016. The flowof fluid through the passages to respective outlets 1016 is controlledby respective electronically-operated valves 1018 receiving controlsignals from the controller 450 via a power field bus 1020. One of thetwo outlets 1016 is connected by a lube supply line 1024 to a firstseries of one or more injectors 1030 that deliver metered amounts oflubricant to points of lubrication 1034 (e.g., bearings) in a first zoneZ1. The other outlet 1016 is connected by a lube supply line 1040 to asecond series of one or more injectors 1044 that deliver metered amountsof lubricant to points of lubrication 1048 (e.g., bearings) in a secondzone Z2. Flow of lubricant to the first and second zones is controlledby selective activation of the electronically-operated valves 1018, asdescribed in the embodiment of FIGS. 12-15. When used with this type oflubrication distribution system, the piston 384 of the pump unit 300moves through venting return strokes, as described above regarding theinjector distribution system 600.

In the embodiment of FIG. 18, the manifold 1008 is constructed the sameas described above regarding FIGS. 13-15, except that the check valves742 in the outlets 1016 are eliminated to allow the injectors 1030, 1044to reset during the return venting strokes of the piston 384.

In the distribution system 1100 of FIG. 19, the controller 450 of thepump unit 300 is programmed to operate the unit to pump the desiredamount of lubricant through a lube supply line 1104 to a manifold 1108having passages in fluid communication with two outlets 1116. The flowof fluid through the passages to respective outlets 1116 is controlledby respective electronically-operated valves 1118 receiving controlsignals from the controller 450 via a power field bus 1120.

In one embodiment, the power field bus 1120 includes a dual cable. Afirst cable of the bus 1120 is a data cable transmitting between thecontroller and the CAN modules. It carries CAN messages to control eachof the CAN modules 1121, 1123 and is connected to each of the modules,such as by a daisy-chain. The first cable also carries CAN messages fromthe CAN modules to the controller (such as sensor signals). A secondcable of the bus 1120 carries power to each of the CAN modules for usein energizing the valves associated with each CAN module. The powercable is connected to relays of each CAN module which energize valves,such as by a daisy-chain. As illustrated in FIG. 19, CAN module 1121 hastwo separate sets of power lines. Each set selectively energizes each ofthe valves 1118 and is connected between the module and its respectivevalves 1118. CAN module 1123 has four separate sets of power lines. Eachset selectively energizes each of its respective valves 1150A-1150D. Asused herein, a relay includes any electrically or mechanically operatedswitch and/or any device to control a circuit by a low-power signal.

One of the two outlets 1116 is connected by a lube supply line 1124 to aseries of injectors 1130 that deliver metered amounts of lubricant topoints of lubrication 1134 (e.g., bearings) in a first zone Z1. Theother outlet 1116 is connected by a lube supply line 1140 to a secondmanifold 1144 having passages in fluid communication with respectiveoutlets 1146 connected to respective points of lubrication 1148A-1148D(e.g., bearings) in a second zone Z2. The flow of fluid through thepassages in the second manifold 1144 is controlled by respectiveelectronically-operated valves 1150A-1150D receiving control signalsfrom the controller 450 via the first cable of the power field bus 1120.CAN module 1123 selectively sequentially connects the valves 1150A-1150Dscheduled for lubrication to the second cable of the power field bus1120 to energize the valves 1150A-1150D. (See FIG. 36A below for anexample of the sequential actuation of the valves 1150A-1150D.) Flow oflubricant to the first and second zones Z1, Z2 is controlled byselective activation of the electronically-operated valves 1118, asdescribed in the embodiment of FIGS. 12-15. CAN module 1121 selectivelyconnects the valves 1118 to the second cable of the power field bus 1120to energize the valves 1118. When used with this type of lubricationdistribution system, the piston 384 of the pump unit 300 moves throughventing return strokes when lubricant is directed to the injectors 1130in the first zone Z1, and the piston moves through non-venting returnstrokes when lubricant is directed to the second manifold 1144 in thesecond zone Z2.

In the embodiment of FIG. 19, the manifold 1108 is constructed the sameas described above regarding FIGS. 13-15, except that the check valve742 in the outlet 1116 connected to the injectors 1130 is eliminated toallow the injectors 1130 to reset during the return venting strokes ofthe piston 384.

In the distribution system 1400 of FIG. 19A the controller 450 of thepump unit 300 is programmed to pump a desired amount of lubricantthrough a lube supply line 1404 to a manifold 1408 having passages influid communication with two outlets 1416. The flow of fluid through thepassages to respective outlets 1416 is controlled by respectiveelectronically-operated valves 1418 receiving control signals and powerfrom the controller 450 via a power field bus 1420. One of the twooutlets 1416 is connected by a lube supply line 1424 to a series ofinjectors 1430 that deliver metered amounts of lubricant to points oflubrication 1434 (e.g., bearings) in a first zone Z1. The other outlet1416 is connected by a lubricant supply line 1440 to a pressure inlet1450 of a reversing 4-way valve 1452. The reversing valve 1452 includesa relief port 1454 connected to a return line 1456 extending to a returnport 1458 on the pump unit 300 in fluid communication with the reservoir304. Two main lubrication lines, 1470A and 1470B, are connected torespective ports, 1472A and 1472B, of the reversing valve 1452. The mainlubrication lines, 1470A and 1470B, deliver lubricant to dual-linemetering valves 1480 that deliver metered amounts of lubricant to pointsof lubrication 1482 (e.g., bearings).

The reversing valve 1452 may be set in either of two positions. In thefirst position, lubricant entering the pressure inlet 1450 travelsthrough the first port 1472A of the valve 1452 to the first mainlubrication line 1470A. When the reversing valve 1452 is in this firstposition, lubricant entering the second port 1472B travels through therelief port 1454 to the return line 1456 and ultimately back to thereservoir 304. When the reversing valve 1452 is in the second position,lubricant entering the pressure inlet 1450 travels through the secondport 1472B of the valve 1452 to the second main lubrication line 1470B.When the reversing valve 1452 is in the second position, lubricantentering the first port 1472A travels through the relief port 1454 tothe return line 1456 and ultimately back to the reservoir 304. Thus,when the valve 1452 is in its first position, lubricant is dispensedunder pressure to the first lubrication line 1470A and the secondlubrication line 1470B is connected to the reservoir 304. When the valve1452 is in its second position, lubricant is dispensed under pressure tothe second lubrication line 1470B and the first lubrication line 1470Ais connected to the reservoir 304. In operation, the reversing valve1452 switches from the first position to the second position as will bedescribed below.

When the reversing valve 1452 is in its first position, lubricantdirected through the first lubrication line 1470A is dispensed underpressure from a first side of each metering valve 1480 to the respectivepoints of lubrication 1482. When the lubricant is dispensed from thelast metering valve 1480, the pump unit 300 continues to operate and thepressure in the first lubrication line 1470A increases until thelubricant in the line reaches a preselected pressure (e.g., 3000 psi).When lubricant in the line 1470A reaches the preselected pressure, thereversing 4-way valve 1452 moves to its second position so it directslubricant through the second lubrication line 1470B and connects thefirst lubrication line 1470A to the reservoir 304 so pressure in thefirst line is relieved. Lubricant directed through the secondlubrication line 1470B is dispensed under pressure from an opposite sideof each metering valve 1480 to the respective points of lubrication1482. When the lubricant is dispensed from the last metering valve 1480,the pressure in the second lubrication line 1470B builds until thelubricant in the line reaches a preselected pressure. When the lubricantreaches the preselected pressure, a signal from an end-of-line pressureswitch (not shown) or a micro switch (not shown) on the reversing valve1452 stops the pump unit 300.

In the embodiment of FIG. 19A, the manifold 1408 is constructed the sameas described above regarding FIGS. 13-15, except that the check valve742 in the outlet 1416 connected to the injectors 1430 is eliminated toallow the injectors 1430 to reset during the return venting strokes ofthe piston 384.

Dual-Line zones, such as zone Z2 of FIG. 19A, can be combined with otherdual-line zones (not shown), combined with divider valve zones (such aszone Z1 shown in FIG. 19B), or used alone (as shown in FIG. 19C) withoutdeparting from the scope of the present invention. As will beappreciated by those skilled in the art, dual-line zones can be usedeffectively with long lines, at high pressures, and/or for hundreds oflubrication points. In addition to the dead-end system illustrated inFIGS. 19A-19C, the dual-line zone can be configured to have otherdual-line system layouts, such as an end-of-the-line system or a loopsystem, depending on its particular application.

Desirably, each of the lube supply lines (e.g., 510, 610, 702, 804, 824,840, 904, 924, 940, 1004, 1024, 1040, 1104, 1124, 1140) deliveringlubricant from the pump unit 300 in the above systems comprises a hosewhich is substantially non-expansible when the pressure is below apredetermined limit (e.g., 1500 psi). To ensure that the proper amountof fluid is delivered by the pump unit to the points of lubrication, itis desirable that the lubricant in the supply lines remain below thislimit. The pressure sensor 372 at the outlet end of the cylinder bore338 is provided for this purpose. The controller 450 is responsive tosignals from this sensor. If the pressure sensed by the sensor 372remains below the stated limit, the controller operates the steppermotor 394 at a predetermined normal speed to pump lubricant at apredetermined rate. If the pressure sensed by the sensor 372 increasesabove the limit, the controller operates the stepper motor 394 at aslower speed to deliver the desired quantity of lubricant at a slowerrate to avoid undesirable expansion of the hose and to avoid undesirableback pressure in the system including the lube supply lines. In oneembodiment, the hose used for the lubricant supply lines has an insidediameter of about 0.250 inch and a length from the pump unit 300 to apoint of lubrication of up to about eighty (80) ft. Desirably, thelength of the lube supply line from the pump unit to the first manifoldof the lubrication distribution unit is no more than about fifty (50)feet.

Desirably, a pump unit 300 of the distribution system 1100 is equippedwith a self-diagnostic system for identifying the reason for a pumpfailure. In this regard, lubrication systems fail for several reasons.First, the pump components wear to a point where they are not capable ofbuilding adequate pressure to operate the lube system. This may be dueto seal wear, piston wear, and/or cylinder wear. Second, the outletcheck valve is unable to hold pressure by preventing back flow in thesystem. This may be due to the valve seat becoming pitted and corroded,or the ball becoming pitted and corroded, or because a contaminantlodges in the valve seat to prevent proper sealing. Third, as theambient temperature decreases, greases may become stiff and difficult topump. At some point, the pressure necessary to move the grease becomesprohibitive. A pump unit equipped with the self-diagnostic systemdescribed below can perform diagnostic tests to determine whether asystem failure is due to any of the above reasons.

In the event the system 1100 fails to pump lubricant properly, theself-diagnostic system runs three diagnostic tests.

To test whether the pump is capable of producing adequate pressure, thecontroller 450 signals the electronically-operated valves 1118 of themanifold 1108 to close their respective bores. The stepper motor 394 isthen operated by the controller 450 to advance the piston 384 a smalldistance in the cylinder bore 338. The pressure at the outlet of thepump cylinder is sensed by the pressure sensor 372. The processor of thecontroller 450 samples pressure readings from the sensor and comparesthese readings to a reference pressure or pressures to determine whetherthe pressure build-up is adequate.

To test whether the check valve 344 is capable of holding adequatepressure, the controller 450 operates the stepper motor 394 to reversethe pump piston 384 a small distance in the cylinder bore 338. Thepressure at the outlet of the pump cylinder is sensed by the pressuresensor 372. The processor of the controller samples pressure readingsfrom the sensor and compares these readings. If the pressure drops, thedropped pressure is indicative of a failure of the check valve 344. Ifthe pressure holds, the check valve is working.

To test whether the grease is too stiff for proper operation, a user ofthe system would conduct what may be referred to as a ventmeter test, asdescribed in U.S. Pat. No. 7,980,118, incorporated by reference herein.To perform this test, the controller 450 operates the stepper motor 394to advance the piston 384 until the pressure as sensed by the pressuresensor 372 at the outlet of the cylinder bore 338 reaches apredetermined pressure (e.g., 1800 psi). The stepper motor is thenoperated to reverse the piston through a venting return stroke to itsvent position, at which point grease in the lube supply line is ventedback to the reservoir. After a delay of predetermined duration (e.g., 30seconds), the pressure at the outlet of the cylinder bore 388 isrecorded. The controller then uses the following equation to determinethe yield stress (Y) of the grease:Y=[pπr ²/2πr1]=pr/21where “p” is the recorded pressure at the cylinder bore outlet after 30seconds; “r” is the radius of the lube supply line 1104; and “l” is thelength of the lube supply line 1104 from the pump unit 300 to the firstmanifold 1108. The values of “r” and “l” are provided to the controllerby user inputting this information via the operator input and/or USBport.

If the calculated yield stress (Y) of the grease is such that it exceedsa known value at which the grease is too stiff for the pump to operateproperly (e.g., a value of 0.125), then the controller 450 will signal awarning to the user. The warning will signal the user to switch over toa grease of a lighter grade.

A pump unit 300 having the self-diagnostic feature described above canbe used with any type of lubrication distribution system in which flowthrough the lube supply line from the pump unit to the points oflubrication can be blocked.

The self-diagnostic system described above can also include a test fordetermining the proper operation of the motor. To perform this test, thecontroller 450 opens an electronically-operated valve 1118 to allow atleast limited flow through the lubrication distribution system. Thecontroller then operates the stepper motor 394 to move the piston 384through successive pumping and return strokes. Movement of the piston issensed by magnetic field sensors 440, 442 mounted on the followerhousing 404. Based on feedback from the sensors, the controller is ableto determine whether the motor 394 is moving the piston back and forththrough its complete range of travel. The test can also be used todetermine the existence of any unwanted binding in the drive mechanism,e.g., due to misalignment of the drive components. This is accomplishedby measuring the amount of electrical current drawn by the motor 394 asit works to move the piston 384. Excessive current draw (e.g., 1.0 ampor more) may indicate unwanted binding of the motor and/or lead screwmechanism. The controller advances the motor slowly, (e.g., 0.75 inchesin 10 seconds) during this test to prevent excessive back pressure inthe system.

The self-diagnostic tests described above can be run automatically inresponse to an error signal indicating a problem with the pump unit orthe lubrication distribution system. In addition, the self-diagnosticgrease stiffness test can be conducted if the temperature of thelubricant in the reservoir, as determined by the temperature sensor 332(FIG. 4), drops below a predetermined temperature.

Additional features of a self-diagnostic system of this invention aredescribed later in this specification.

It will be observed from the foregoing that a pump unit 300 of thisinvention has many advantages. For example, the controller 450 isprogrammed to operate the pump in the following modes:

-   -   (i) in a divider valve mode in which lubricant from the pump is        fed to one more divider valves for delivery to multiple        lubrication points;    -   (ii) an injector mode in which lubricant from the pump is fed to        a plurality of lubricant injectors for delivery to multiple        lubrication points;    -   (iii) in a dual line system mode in which lubricant from the        pump is fed to a plurality of lubricant injectors for delivery        to multiple lubrication points and having reversing valves for        venting lubricant to the reservoir; and    -   (iv) a CAN-bus mode        -   (a) in which lubricant from the pump is fed to a plurality            of solenoid-operated valves for delivery to multiple            lubrication points,        -   (b) CAN messages which control the solenoids are provided            via the field bus, and        -   (c) power to energize the solenoids is provided via the            field bus.            The fact that the stirrer 320 and pump piston 384 are driven            by two separate drive mechanisms also allows the stirrer and            piston to be driven independently of one another so that            lubricant in the reservoir can be fluidized before the            stepper motor is operated to reciprocate the piston to pump            the lubricant. The movement of the stirrer also functions to            prime the pump by forcing lubricant through the reservoir            outlet directly (i.e., along a defined flow path) into the            inlet of the pump cylinder.

The pump unit 300 is capable of pumping viscous lubricants at relativelylow temperatures. This is due, at least in part, to the strong push/pullforces exerted on the lubricant to force lubricant from the reservoir304 directly into the cylinder bore 338. As explained above, rotation ofstirrer 320 causes the force-feed mechanism 330 to exert a strongdownward force on lubricant in the interior of the reservoir 304 tendingto push it along a defined flow path (e.g., as shown in FIG. 6) into thecylinder bore 338. Further, a return stroke of the piston 384 generatesa force tending to pull this same lubricant along the same defined flowpath. The combination of these pushing and pulling forces is effectivefor moving viscous lubricant into the cylinder bore 338 at lowertemperatures.

Other advantages of this invention are apparent. The use of two separatedrive mechanisms (one to drive the stirrer and one to drive the piston),and particularly the use of a linear position motor (e.g., a steppermotor), eliminates much of the complexity of conventional pumping units.The pump unit operates efficiently to pump lubricant over a wide rangeof temperatures. And the multiple feed lines of the pumping unit providegreater flexibility when installing the system in the field.

Further, the pump unit may include diagnostic software for performingdiagnostic tests to determine one or more of the following:

-   -   (i) an ability of the pump to generate a minimum pressure at the        cylinder outlet;    -   (ii) an ability of the check valve to block reverse flow through        the outlet;    -   (iii) whether the grease in the reservoir is too stiff to be        pumped by the pump; and    -   (iv) an amount of electrical current drawn by a motor of the        drive mechanism as the piston moves in the cylinder bore.

FIG. 20 illustrates an alternative linear position drive mechanism,generally designated 1200, for reciprocating the piston 384 of the pumpunit 300. The drive mechanism of this embodiment is similar to thestepper motor drive mechanism of the previous embodiment. However, thedrive mechanism comprises a reversible motor 1204 that is not a steppermotor. Position designators 1210 on the follower 1214 are readable by aposition sensor 1220 on the follow housing 1224. The position sensor1220 is connected to the controller 1226 of the pump unit for signalingthe longitudinal position of the follower 1214 and the piston 1230attached to the follower. The controller 1226 operates the reversiblemotor 1204 to rotate the lead screw 1240 in one direction to move thefollower and piston a suitable distance (as determined by the positionsensor) through a pumping stroke and in the opposite direction to movethe follower and piston a suitable distance (as determined by theposition sensor) through a return stroke.

By way of example, the position designators 1210 on the follower 1214may be raised metal segments spaced along the follower at predeterminedintervals, and the position sensor 1220 may be an inductive sensor whichdetects and counts the segments and signals the controller. Thecontroller 1226 monitors the linear position of the follower and, basedon this information, is able to move the piston a distance to necessaryto dispense a desired amount of grease to the point of lubrication.Alternatively, the position designators 1210 on the follower may besegments of magnets spaced along the follower at predeterminedintervals, and the position sensor 1220 may be a magnetic field sensorwhich detects and counts the segments and signals the controller. Thecontroller monitors the linear position of the follower and, based onthis information, is able to move the piston a distance to necessary todispense a desired amount of grease to the point of lubrication.

The linear position designators 1210 and sensor 1220 can also be used todetermine when the piston 1230 is at the extreme limits of its travel.This information can be used for calibration of the system. When thesystem is activated the first time, the system is calibrated so thecontroller knows the position of the piston at the limits of itsmovement.

Other linear position drive mechanisms may be used.

FIG. 21 illustrates another embodiment of a linear position drivemechanism, generally designated 1300, for reciprocating the piston ofthe pump unit 300. The drive mechanism of this embodiment is similar tothe drive mechanism of the previous embodiment (FIG. 20) except that theposition of the follower 1314 and piston 1330 is determined by anencoder device, generally designated 1340. The encoder device 1340 ismounted in the follower housing 1346 and comprises a rotatable cylinder1350 affixed to (e.g., pressed on) a surface of the lead screw 1356rotated by the motor 1370, which is a reversible motor but not a steppermotor. As the cylinder 1350 rotates, the encoder 1340 monitors theangular rotational movement of the cylinder and signals the extent ofsuch movement to the controller 1380 of the pump unit. Based on thisinformation, the controller can determine the linear position of thepiston 1330, as will be understood by those skilled in the art. Thecontroller 1380 also controls the operation of the motor 1370 to movethe piston the appropriate distances during its pumping and returnstrokes. Position sensors 1380, 1382 are provided on the followerhousing 1346 for calibrating the encoder 1340 with respect to theposition of the follower 1314 (and thus the piston 1330). By way ofexample, these position sensors 1380, 1382 may be magnetic field sensorsmounted on the follower housing 1346 for sensing a magnet (not shown) onthe follower, as in the stepper motor embodiment described above.

Referring briefly to FIG. 37 (which is described in detail below), asystem 2300 of the invention includes the pump unit 300 described above,an alarm 2330, and sensors 2322, 2324, 2326, 2358 for sensing conditionsof the system and providing condition signals. A controller 2308controls the operation of the pump motor 394 by selectively energizingthe motor to reciprocate the piston 384. The controller is responsive tocondition signals from the sensors 2322, 2324, 2326, 2358 to selectivelyenergize the alarm when a condition signal is outside a preset range. Inone embodiment, the controller is a processor including a tangible,computer readable non-transitory storage medium. The storage mediumstores processor executable instructions for controlling the operationof the processor. In this embodiment, the processor is programmed by anoperator to execute one or more self-diagnostic sets of instructions asillustrated in FIGS. 22-36.

As used herein, a line pressure transducer (“line PT” hereinafter) isany pressure sensor sensing pressure in a lube supply line 2302, e.g.,sensors 2324, 2326, 2346, 2347, and 2348 in FIGS. 37 and 37A. Anend-of-line pressure transducer is a lube supply line pressuretransducer at a location immediately upstream from the last injector ofa series of one or more injectors of an injector distribution system,e.g., sensor 2347 in FIG. 37A. An internal or pump pressure transducer(“internal PT” or “pump PT” hereinafter”) is any pressure sensor sensingpressure at the cylinder outlet of the pump unit, e.g., sensor 372 inFIG. 4, sensor 2726 in FIG. 49, and sensor 2352 in FIGS. 37 and 37A.

FIGS. 22-28 illustrate flow diagrams of one embodiment of the inventionof instructions for execution by a processor to provide self-diagnosticsfor a lubrication system having a closed loop, injector system with aninternal (pump) PT.

FIGS. 24-29 illustrate flow diagrams of one embodiment of the inventionof instructions for execution by a processor to provide self-diagnosticsfor a lubrication system having an open loop, non-injector system withan internal (pump) PT.

FIGS. 26, 30-35 illustrate flow diagrams of one embodiment of theinvention of instructions for execution by a processor to provideself-diagnostics for a lubrication system having a closed loop, injectorsystem without an internal (pump) PT. In this embodiment, stepper motorcurrent is monitored as indicative of pressure.

FIGS. 26, 32-36 illustrate flow diagrams of one embodiment of theinvention of instructions for execution by a processor to provideself-diagnostics for a lubrication system having an open loop,non-injector system without an internal (pump) PT. In this embodiment,stepper motor current is monitored as indicative of pressure.

FIGS. 22-28 illustrate an injector system with an internal (pump) PT.The user defined settings input by the user for this system include:

-   -   (1) an off-timer setting corresponding to the maximum time        between the end of one lube event and the start of the next lube        event (as used herein, “lube event” means a lubrication cycle        for the injector(s) of an injector distribution system, or a        lubrication cycle for the divider valve(s) of a divider valve        distribution system, or a lubrication cycle for the valve(s) of        a CAN bus distribution system);    -   (2) an alarm time setting corresponding to a maximum time from        the start to the completion of a lube event, failing which an        alarm is activated;    -   (3) a maximum pressure setting corresponding to a maximum        pressure (e.g., 3000 psi) allowed at the cylinder outlet of the        pump unit as sensed by the internal (pump) PT;    -   (4) an injector-activation pressure setting corresponding to a        pressure (e.g., 2500 psi) sensed by an end-of-line PT needed to        activate the injectors;    -   (5) a vent pressure setting (also referred to hereinafter as an        injector-reset pressure setting) corresponding to a minimum        pressure (e.g., 900 psi) needed to reset the injectors of the        system;    -   (6) a length of the lube supply line; and    -   (7) a diameter of the lube supply line.

FIG. 29 illustrates a divider valve system with an internal (pump) PT.The user defined settings for the system include an off-timer settingcorresponding to the time between lube events (defined in the precedingparagraph); an alarm time setting (defined in the preceding paragraph);a maximum pressure setting (defined in the preceding paragraph); thelength of the lube supply line; and the diameter of the lube supplyline.

FIGS. 30-35 illustrate an injector system without an internal PT. Theuser defined settings include an off-timer setting (defined above); analarm time setting (defined above); a maximum pressure settingcorresponding to a maximum pressure (e.g., 3000 psi) allowed at thecylinder outlet of the pump unit as sensed by a stepper motor currentsensor; an injector-activation pressure setting (defined above); and avent pressure setting (defined above).

FIG. 36 illustrates a divider valve system without an internal PT. Theuser defined settings for the system include an off-timer setting(defined above); an alarm time setting (defined above); and a maximumpressure setting corresponding to a maximum pressure (e.g., 3000 psi)allowed at the cylinder outlet of the pump unit as sensed by a steppermotor current sensor.

FIG. 22 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having a closed loop, injector system with aninternal PT. At 1502, an off timer in the processor begins a time downto the next lube event. At 1504, the off timer times out and theprocessor energizes the stirrer motor 326 to drive the stirrer 320 ofthe pump unit 300 to stir lubricant in the reservoir 304. The stirrermotor 326 turns on for a preset time (e.g., 15 seconds) prior to thepump stepper motor 394 turning on to begin stirring the lubricant. Thestirrer motor continues to run until the pump stepper motor 394 turnsoff. At 1506, the processor reads the end-of-line PT(s) to confirm thatthe line pressure is below the vent pressure setting to reset theinjectors. If the pressure is at or above the vent pressure setting, theprocessor executes the instructions in FIG. 23. If the pressure is belowthe vent pressure setting, the processor begins timing an alarm at 1508and the pump stepper motor 394 starts or continues to build pressure at1510. At 1512, the processor indicates on display 456 the pressure atthe cylinder outlet of the pump unit, as sensed by the internal (pump)PT.

At 1514 in FIG. 22 (a closed loop system), the internal (pump) PT ismonitored by the processor and the speed of the stepper motor 394 isadjusted by the processor according to the lube pressure at the cylinderoutlet of the pump unit. For example, a lookup table based onpredetermined values adjusts the software commands to control speedand/or torque of the stepper motor (e.g., motor voltage, motor current,pulse duty cycle (pulse frequency), and/or pulse power). At higherpressure, the stepper motor rotates at slower speeds.

At 1516, the processor proceeds to implement the steps in FIG. 24 if thecylinder outlet pressure has exceeded a maximum. At 1518, the processorproceeds to implement the steps in FIG. 25 if the magnetic field sensor442 of the pump unit 300 has not indicated that the piston is at the endof its power stroke (indicating an incomplete stroke). At 1520, theprocessor proceeds to implement the steps in FIG. 26 if a low levelswitch of the reservoir 304 has closed (indicating that the level oflubricant in the reservoir is low). At 1522, the processor proceeds toimplement the steps in FIG. 27 if the alarm time setting is exceeded(indicating that a lube event is taking longer to complete than a presettime period such as 15 minutes). At 1524, the processor proceeds toimplement the steps in FIG. 28 if the stirrer motor current has exceededa maximum current limit (indicating for example, that the lubricant inthe reservoir 304 is excessively stiff).

At 1526 in FIG. 22, the processor checks the internal (pump) PT andreturns to 1510 if the internal (pump) pressure has not reached theinjector-activation pressure setting previously input by the user. Ifthe internal pressure has reached or exceeded the injector-activationpressure setting, the pump stepper motor 394 is stopped by the processorat 1528. The processor determines at 1530 whether the alarm time settinghas been exceeded. If it has been exceeded, the processor implements thesteps in FIG. 27. If it has not been exceeded, the processor determinesat 1532 whether the end-of-line pressure sensed by the end-of-line PT(s)has reached the injector-activation pressure setting, e.g., 2500 psi. Ifthe end-of-line pressure has reached the injector-activation pressuresetting, the processor controls the stepper motor to return the pumppiston to its vent position at 1534 (see FIG. 9). The stirrer motor 326runs for a preset period (e.g., 15 seconds) at 1535 and then the offtimer begins again at 1502. If the end-of-line pressure has not reachedthe injector-activation pressure setting, the processor returns to 1526to check the internal (pump) PT. If the pressure sensed by the internalPT is below the injector-activation pressure setting, pumping (i.e.,operation of the stepper motor) continues at 1510. If the pressuresensed by the internal PT has reached the injector-activation pressuresetting at 1526, pumping (i.e., operation of the stepper motor) stops at1528 and the processor proceeds as noted above. The stirrer motor 326runs at 1535 to operate after a lube event is over to fluidize thelubricant and prepare the lubricant in the reservoir for the next lubeevent by priming the pump cylinder (if needed) with lubricant for thenext lube event.

In FIG. 22, for a system with a stirrer, a lube event is the timebetween the end of one lube event at 1535 with the end of the presetperiod of the operation of the stirrer motor and the start of the nextlube event at 1504 with the start of the stirrer motor. It is alsocontemplated that a system may not have a stirrer and operate in amanner similar to FIG. 22. In FIG. 22, for a system without a stirrer, alube event is the time between the end of one lube event at 1534 withthe pump piston returning to its vent position and the start of the nextlube event at 1510 with the start of the stepper motor.

FIG. 23 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a vent (ventmeter)test for a lubrication system having a closed loop, injector system withan internal PT. From 1506 of FIG. 22, as 1540 indicates, at the start ofa lube event the pressure sensed by the end-of-line PT(s) is above thevent pressure setting input by the user. At 1542, the processor startsthe ventmeter test (described earlier in this specification) byreversing the pump stepper motor 394 and returning the pump piston 384to its vent position at 1544. Then, the lube event restarts and the pumpstepper motor 394 is operated to build the internal pressure to a presetlevel (e.g., 1800 psi). The processor reverses the motor to return thepiston to the vent position, waits a preset time (e.g., 30 seconds), andthen reads the internal (pump) PT at 1566. Using the internal (pump) PTpressure reading, supply line length, and supply line diameter, theyield stress of the lubricant (e.g., grease) is determined at 1568 usingthe ventmeter test described above. The results of the test are thencompared to a preset level of yield stress (e.g., 1000 pascals) at 1570.

If the yield stress determined at 1570 is less than the preset level(e.g., 1000 pascals), the processor indicates the positive (passing)ventmeter test results on the display 456 at 1572. At 1574 the processordiscontinues any more timed lube events and activates an alarm. Thedisplay 456 shows both a failure to vent at the end of the lube supplyline and the positive results of the ventmeter test. From this it can beassumed that the end-of-line PT pressure reading is above the ventpressure setting due to some problem other than excessive lubricantstiffness.

On the other hand, if the yield stress determined at 1570 by theventmeter test is greater than the preset level (e.g., 1000 pascals),the processor indicates the negative (failing) ventmeter test results onthe display 456 at 1576. At 1578 the processor discontinues any moretimed lube events and activates the alarm. The display 456 shows both afailure to vent at the end of the lube supply line and that thelubricant (e.g., grease) failed the ventmeter test. This resultindicates that the end-of-line PT pressure reading is above the ventpressure setting at 1506 because of excessive lubricant stiffness.

FIG. 24 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a maximum pressuretest for a lubrication system having either a closed loop, injectorsystem with an internal (pump) PT or an open loop, non-injector systemwith an internal (pump) PT. From 1516 of FIGS. 22 and 29, as 1580indicates, the maximum pressure setting at the pump cylinder outlet hasbeen exceeded. At 1582, the stepper motor is immediately stopped by theprocessor and reversed to return the pump piston to the vent position.At 1584, a lube event is initiated once the pressure has vented. At1586, if the maximum pressure setting at the pump cylinder outlet isexceeded a second time, the processor shuts off the stepper motor at1588 and no more lube events will occur. The pressure alarm is activatedand the display 456 will indicate a blocked supply line. If the maximumpressure setting is not exceeded, the processor at 1586 returns to 1502to start a normal lube event and the off timer begins to time out.

FIG. 25 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to conduct a full-stroke testof a piston for a lubrication system having either a closed loop,injector system with an internal (pump) PT or an open loop, non-injectorsystem with an internal (pump) PT. From 1518 of FIGS. 22 and 29 as 1590indicates, during pump stepper motor operation, the forward magneticsensor 442 (e.g., a reed switch) did not close when the stepper 394motor reversed for its return stroke (indicating that the stepper motor394 did not move the piston to its forward position as sensed by theforward sensor 442). At 1592, the processor determines if this is thesecond time that the forward reed switch failed to close during a lubeevent or a set period. If yes, at 1594 the processor uses the lastinternal (pump) PT pressure reading to adjust the stepper motoroperation. For example, if the stepper motor is being operated accordingto a profile as illustrated and described with regard to FIGS. 56-58(below), then the processor uses the last internal (pump) PT pressurereading to adjust the stepper motor operation to a slower speedaccording to a lookup table. At 1596, the processor moves the piston toits vent position, and the processor then returns to 1510 (FIG. 22 forinjector systems and FIG. 29 for divider valve systems) to initiateanother lube event. If the forward reed switch fails to close again at1598, the pump stepper motor is shut off at 1600, and the processordiscontinues anymore timed lube events. Also, a pressure alarm isactivated by the processor and the display 456 indicates that forwardreed switch failed to close. If the forward reed switch does not fail at1598, the processor returns to 1502 (FIG. 22 for injector systems andFIG. 29 for divider valve systems) to begin the off timer for the nextevent since a normal lube event has occurred. If the forward reed switchhas not failed to close a second time at 1592, at 1602, the processorreturns the piston to its vent position and implements the activity at1510 (FIG. 22 for injector systems and FIG. 29 for divider valvesystems) to initiate another lube event. If the forward reed switchfails to close again at 1604, the processor returns to 1592. If not, theprocessor returns to 1502 (FIG. 22 for injector systems and FIG. 29 fordivider valve systems) to begin the off timer for the next event since anormal lube event has occurred. In one embodiment, the reed switch is apiston sensor providing a piston signal indicative of the position ormovement of the piston.

FIG. 26 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a reservoir leveltest for a lubrication system having either a closed loop, injectorsystem or an open loop, non-injector system, each with or without aninternal (pump) PT. From 1520 of FIGS. 22, 29, 30 and 36 as 1606indicates, the low level reservoir switch may close during a pumpingoperation. If this occurs, the processor waits until the lube eventcompletes and the pump stepper motor 394 shuts off. At 1608, if the userhas set the software operating the processor to allow additional lubeevents when the low level switch is closed, the processor proceeds to1610 to indicate on display 456 a low level alarm. At 1613, the pumppiston returns to the vent position and vents. The processor proceeds to1502 (FIG. 22 for injector systems with an internal PT; FIG. 29 fordivider valve systems with an internal PT; FIG. 30 for injector systemswithout an internal PT; FIG. 36 for divider valve systems without aninternal PT) to start the off timer until the next lube event. At 1608,if the user has not set the software operating the processor to allowadditional lube events when the low level switch is closed, theprocessor proceeds to 1614. The pump stepper motor does not restartagain until reservoir has been filled. The processor indicates a lowlevel alarm on the display 456, and a low level alarm relay isenergized. When the reservoir is refilled, the processor goes to 1510(FIG. 22 for injector systems with an internal PT; FIG. 29 for dividervalve systems with an internal PT; FIG. 30 for injector systems withoutan internal PT; FIG. 36 for divider valve systems without an internalPT).

FIG. 27 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a cycle (i.e.,injector reset) time-out test for a lubrication system having either aclosed loop, injector system with an internal (pump) PT or an open loop,non-injector system with an internal (pump) PT. From FIGS. 22 and 29 asindicated at 1620, the alarm time was exceeded at 1524 or 1530. Inresponse, the processor initiates an outlet check test at 1622 todetermine whether the outlet check valve and/or the check valve seat areworking properly or are defective. The piston of the pump unit 300 isreturned to the vent position at 1624. After venting, the pump steppermotor 394 is started and builds the pressure. The pump stepper motor 394is stopped by the processor when the pressure sensed by the end-of-linePT 2346 equals or exceeds a preset setting (e.g., 1000 psi), which maybe previously input or adjusted by the user. At 1626, the pump piston384 is returned to the start (vent) position and the processor waits aset time period (e.g., 20 seconds). At 1628, the processor determines ifthe pressure as sensed by the end-of-line PT 2346 has dropped more thana set amount (e.g., 500 psi). If yes, no more timed lube events will beinitiated by the processor at 1630. The processor activates a pressurealarm and controls the display 456 to indicate that the alarm timesetting was exceeded due to a defective outlet check valve 344 and/orcheck valve seat 348.

If the pressure has dropped less than the set amount, the processorproceeds to 1632 and initiates a ventmeter test (described above). At1634, the pump piston is returned to the vent position and the processoroperates the pump stepper motor to build the internal pressure to a setamount (e.g., 1800 psi) and then stops the pump stepper motor. At 1636,the pump piston 384 is returned to the vent position and the processorwaits a set time period (e.g., 30 seconds) to read the internal pumppressure. The processor then completes the ventmeter test using theinternal (pump) PT pressure reading at 1638, supply line length, andsupply line diameter to determine the yield stress of the grease. If thedetermined yield stress is greater than the set yield stress level(e.g., 1000 pascals) at 1640, the processor will indicate the negative(failing) ventmeter test results on the display 456 at 1642. At 1644,the processor discontinues any more timed lube events, and the alarm isactivated by the processor. If the determined yield stress is less thanthe set yield stress level (e.g., 1000 pascals) at 1640, the processorwill indicate the positive (passing) ventmeter test results on thedisplay 456 at 1646. At 1648, the processor will increase the alarm timesetting by a set amount (e.g., 50%) and initiate a lube event at 1508(FIG. 22 for injector systems and FIG. 29 for divider valve systems). Ifthe increased alarm time setting is not exceeded at 1650, a normal lubeevent has occurred and the processor proceeds to 1502. Optionally, at1654, the next lube event and those following will be monitored by theprocessor to determine if the alarm time setting can be adjusted to theoriginal user setting. If the increased alarm time setting is exceededat 1650, and the processor determines at 1656 that this is not thesecond time that the alarm time setting has been increased, theprocessor proceeds back to 1648. If it is the second time, the processorproceeds to 1658. No more timed lube events are initiated by theprocessor and an alarm is activated. The display 456 indicates that thealarm time has been exceeded.

FIG. 28 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a reservoirlubricant stiffness test for a lubrication system having either a closedloop, injector system with an internal (pump) PT or an open loop,non-injector system with an internal (pump) PT. From FIGS. 22 and 29 asindicated at 1660, the stirrer motor 326 has exceeded its maximumcurrent limit at 1626 so the stirrer motor is immediately stopped at1662 and a ventmeter test is performed at 1664 with the stirrer motorturned off. The processor returns to 1544 of FIG. 23 for a ventmetertest, returning the pump piston to its vent position and starting thepump stepper motor to build the internal pressure at the pump cylinderoutlet to the preset setting (e.g., 1800 psi). As an alternative or inaddition to performing a ventmeter test at 1664, the processor mayenergize a heater to heat the lubricant. For example, a heater in thepump housing of the pump unit, or in the reservoir of the pump unit, ora heating element associated with a lube line, may be activated toreduce the lubricant stiffness. As noted below, stiff lubricant may bedispensed by overdriving the stepper motor for a period of time. In oneembodiment, a heater may be activated and the stepper motor overdrivenin order to dispense stiff lubricant. If lubricant in the reservoir isheated, the stirrer motor which was stopped at 1662 may be energizedagain because the lubricant in the reservoir has been heated and itsviscosity reduced.

FIG. 29 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having either an open loop, non-injector (e.g.,divider valve) system with an internal (pump) PT. FIG. 29 is the same asFIG. 22 except that 1506 is bypassed and 1526-1532 are replaced by1702-1704. In divider valve systems such as represented by FIG. 29, atleast one divider valve (e.g., a master divider valve) includes aproximity switch, such as an inductive switch, which is set when thedivider valve moves to fill with lubricant and which is reset (i.e., theswitch is activated) when the divider valve moves to empty and dispensethe lubricant. At 1702, the processor confirms that the proximity switchof the divider valve has not been activated, indicating that the valvehas not dispensed lubricant, and continues operation of the pump steppermotor 394 at 1510. If the proximity switch has been activated, the pumpstepper motor stops at 1704 and the piston 384 is returned to its startposition at 1533 (i.e., a non-venting start position; see FIG. 8). Thestirrer motor 326 runs for a preset period (e.g., 15 seconds) at 1535and then the off timer begins again at 1502.

In FIG. 29, for a system with a stirrer, a lube event is the timebetween the end of one lube event at 1535 with the end of the presetperiod of the operation of the stirrer motor and the start of the nextlube event at 1504 with the start of the stirrer motor. It is alsocontemplated that a system may not have a stirrer and operate in amanner similar to FIG. 29. In FIG. 29, for a system without a stirrer, alube event is the time between the end of one lube event at 1533 withthe pump piston returning to its start position and the start of thenext lube event at 1510 with the start of the stepper motor.

FIG. 30 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having a closed loop, injector system withoutan internal (pump) PT. FIG. 30 is the same as FIG. 22 except that 1506connects to FIG. 31 instead of FIG. 23; 1512-1514 have been replaced by1802; 1516 is replaced by 1803; 1518, 1522, 1524 connect of FIGS. 33,35, 36 instead of FIGS. 25, 27, 28; and 1526-1532 are replaced by1804-1806. After the pump stepper motor 394 starts or continues to buildpressure at 1510, the processor at 1802 monitors the current applied tothe stepper motor and the speed of the motor is adjusted according tomotor current. The applied current is indicative of the internal (pump)pressure at the cylinder outlet of the pump unit. A lookup table basedon predetermined values is used by the processor to control the motorsuch as by adjusting the stepper motor voltage, adjusting availablestepper motor current, adjusting applied power and to adjust the dutycycle (pulse frequency) width modulated (PWM) pulses applied to themotor to control and regulate the internal (pump) pressure. At highermotor currents, the stepper motor rotates at slower speeds. At 1804, ifthe end-of-line PT indicates that the end-of-line pressure has reachedthe injector-activation pressure setting necessary to activate theinjectors, the pump stepper motor is stopped at 1806 and the processorproceeds to 1534. Otherwise, the pump stepper motor continues to operateand the processor proceeds to 1510.

In FIG. 30, for a system with a stirrer, a lube event is the timebetween the end of one lube event at 1535 with the end of the presetperiod of the operation of the stirrer motor and the start of the nextlube event at 1504 with the start of the stirrer motor. It is alsocontemplated that a system may not have a stirrer and operate in amanner similar to FIG. 30. In FIG. 30, for a system without a stirrer, alube event is the time between the end of one lube event at 1534 withthe pump piston returning to its vent position and the start of the nextlube event at 1510 with the start of the stepper motor.

FIG. 31 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to conduct a ventmeter testfor a lubrication system having a closed loop, injector system withoutan internal (pump) PT. At 1506 of FIG. 30, the processor determines thatthe pressure reading from the end-of-line PT is below the vent pressuresetting so the processor proceeds to FIG. 31. At 1810 in FIG. 31, at thestart of the lube event, the pressure reading from the end-of-line PT isabove the vent pressure setting set by the user. As a result, no moretimed lube events are executed by the processor at 1812. The processoractivates the alarm and controls the display 456 to show a failure tovent at the end of the lube supply line.

FIG. 32 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a maximum pressuretest for a lubrication system having either a closed loop, injectorsystem without an internal (pump) PT or an open loop, non-injectorsystem without an internal (pump) PT. From 1803 of FIGS. 30 and 36, as1814 indicates, the maximum stepper motor current driving the pumpstepper motor has been exceeded. At 1816, the stepper motor isimmediately stopped by the processor and reversed to return the pumppiston to its vent position. At 1818, a lube event is initiated once thepressure has vented. At 1820, if the maximum motor current has beenexceeded a second time, the processor shuts off the stepper motor at1822 and no more lube events will occur. The pressure alarm relay isactivated and the display 456 will indicate a blocked supply line. Ifthe maximum motor current is not exceeded at 1820, the processor at 1820returns to 1502 (FIG. 30 for injector systems and FIG. 36 for dividervalve systems) to start a normal lube event and the off timer begins totime out.

FIG. 33 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide full stroke testfor a piston of a lubrication system having either a closed loop,injector system without an internal (pump) PT or an open loop,non-injector system without an internal (pump) PT. FIG. 33 is the sameas FIG. 25 except that 1594 has been replaced by 1824, which uses thelast stepper motor current reading to adjust the motor to the slowestspeed, as indicated by a lookup table. FIG. 33 proceeds from FIGS. 30and 36 at 1518. If the reed switch does not fail to close again at 1598or 1604, the processor returns to 1502 (FIG. 30 for injector systems andFIG. 36 for divider valve systems).

FIG. 34 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a cycle (i.e.,injector reset) time out test for a lubrication system having either aclosed loop, injector system without an internal (pump) PT or an openloop, non-injector system without an internal (pump) PT. FIG. 34 is thesame as FIG. 27 except that 1622-1646 have been bypassed. FIG. 34proceeds from FIGS. 30 and 36 at 1522. After increasing the alarm timeat 1648, the processor returns to 1508 (FIG. 30 for injector systems andFIG. 36 for divider valve systems), or the processor returns to 1502(FIG. 30 for injector systems and FIG. 36 for divider valve systems), orthe alarm is activated at 1658.

FIG. 35 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide a stiffness testfor lubricant in the reservoir for a lubrication system having either aclosed loop, injector system without an internal (pump) PT or an openloop, non-injector system without an internal (pump) PT. From 1524 ofFIGS. 30 and 36, as 1840 indicates, the stirrer motor 326 has exceededits maximum current limit. At 1842, the stirrer motor is stopped and at1844, the processor discontinues timed lube events. An alarm isactivated and the display 456 indicates excessive stirrer motor current.

FIG. 36 is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a lubrication system having an open loop, non-injector (dividervalve) system without an internal (pump) PT. FIG. 36 is the same as FIG.30 except that 1872 replaces 1804. At 1802, in an open loop system thecurrent applied to the stepper motor is monitored and the speed of themotor is adjusted by the processor according to motor current to controland adjust the internal or pump pressure. A lookup table based onpredetermined values will adjust the stepper motor voltage, availablemotor current and the software commands to the motor. At higher motorcurrents, the stepper motor operates at slower speeds. At 1872, theprocessor confirms that the proximity switch monitoring a divider valveof the system has not been activated, indicating that the divider valvehas not reset, and continues operation of the pump at 1510. If theproximity switch has been activated, the pump stepper motor is shut offat 1806 and the piston is returned to its start (non-venting) positionat 1533.

In FIG. 36, for a system with a stirrer, a lube event is the timebetween the end of one lube event at 1535 with the end of the presetperiod of the operation of the stirrer motor and the start of the nextlube event at 1504 with the start of the stirrer motor. It is alsocontemplated that a system may not have a stirrer and operate in amanner similar to FIG. 36. In FIG. 36, for a system without a stirrer, alube event is the time between the end of one lube event at 1533 withthe pump piston returning to its start position and the start of thenext lube event at 1510 with the start of the stepper motor.

FIG. 36A is a flow diagram of one embodiment of the invention ofinstructions for execution by a processor to provide self-diagnosticsfor a CAN bus lubrication system having actuator valves without aninternal pressure transducer such as illustrated in FIG. 19. FIG. 36A isthe same as FIG. 36 except that 1508 and 1522 relating to the alarmtimer and 1872 relating to the proximity switch are eliminated becausethis system does not have divider valves as does the system of FIG. 36.Thus, there is no alarm time setting corresponding to a maximum timefrom the start to the completion of a lube event. In this system, a lubeevent involves opening an actuator valve for a preset period of time (orfor a preset number of pump stokes or a preset number of stepper motorrotations) in order to dispense a preset amount of lubricant through theopen valve to its respective lubrication point.

As an example of the operation of a system according to FIG. 36A,reference will be made to FIG. 19. This example assumes that bearings1148A and 1148B are scheduled for a volume of lubricant deliveryrequiring 30 seconds of stepper motor operation and that bearing 1148Dis scheduled for a volume of lubricant delivery requiring 45 seconds ofstepper motor operation. Bearing 1148C is not scheduled for lubricationin this example. At 1830, the right valve 1118, which is the zonesolenoid for zone Z2, is energized (opened) via the CAN module 1121. At1831, the first valve 1150A associated with bearing 1148A scheduled forlubrication is energized (opened) and the pump stepper motor starts at1510. At 1832, the processor determines if the volume of lubricantoutput by the pump matches the user programmed value for bearing 1148A(e.g., 30 seconds). If not, the pump stepper motor continues to operate.When valve 1150A has been open for 30 seconds (or for a preset number ofpump stokes or a preset number of stepper motor rotations, the processorproceeds from 1832 to 1833. Since valve 1150A is not the last valve inzone Z2 scheduled for lubrication, the processor proceeds to 1831 tosequentially close valve 1150A and open valve 1150B. When valve 1150Bhas been open for 30 seconds (or for a preset number of pump stokes or apreset number of stepper motor rotations), the processor proceeds from1832 to 1833. Since valve 1150B is not the last valve in zone Z2scheduled for lubrication, the processor proceeds to 1831 tosequentially close valve 1150B and open valve 1150D. When valve 1150Dhas been open for 45 seconds (or for a preset number of pump stokes or apreset number of stepper motor rotations), the processor proceeds from1832 to 1833. Since valve 1150D is the last valve in zone Z2 scheduledfor lubrication, the processor proceeds to 1834 to stop the pump steppermotor and then to 1835 to close valves 1150D and the right valve 1118,which is the zone solenoid for zone Z2.

In FIG. 36A, for a system with a stirrer, a lube event is the timebetween the end of one lube event at 1535 with the end of the presetperiod of the operation of the stirrer motor and the start of the nextlube event at 1504 with the start of the stirrer motor. It is alsocontemplated that a system may not have a stirrer and operates in amanner similar to FIG. 36A. In FIG. 36A, for a system without a stirrer,a lube event is the time between the end of one lube event at 1533 withthe pump piston returning to its start position and the start of thenext lube event at 1510 with the start of the stepper motor.

Thus, as shown in FIGS. 22-37A, embodiments of the system of theinvention includes the controller 2308 such as a processor and furthercomprises a tangible, computer readable non-transitory storage mediumincluding processor executable instructions. The processor executes theinstructions, and the instructions include at least one or more of:

-   -   (i) instructions for determining whether a lubricant injector        connected to the system is venting and for energizing the alarm        when the ventmeter test indicates that the injector is not        venting (FIGS. 23 and 31);    -   (ii) instructions for determining a lubricant pressure at the        pump and for energizing the alarm when the determined pressure        is greater than a maximum pressure (FIGS. 24 and 32);    -   (iii) instructions for determining a piston movement and for        energizing the alarm when the determined piston movement is less        than a minimum movement (FIGS. 25 and 33);    -   (iv) instructions for determining a lubricant level of the        reservoir and for energizing the alarm when the determined        lubricant level is less than a minimum level (FIG. 26);    -   (v) instructions for determining a lubricant pressure and for        energizing the alarm when the determined pressure is less than a        maximum pressure after a given period of time of motor pump        operation has elapsed (FIGS. 27 and 35);    -   (vi) instructions for monitoring a current applied to the        stirrer motor and for discontinuing operation of the stirrer        motor when the stirrer motor current exceeds a maximum (FIG.        28); and    -   (vii) instructions for monitoring a current applied to the        stirrer motor 326 and for energizing the alarm when the stirrer        motor current exceeds a maximum (FIG. 35).

FIG. 37 is a block diagram of one embodiment of a CAN bus lubricationsystem 2300 of the invention for supplying lubricant to zones ofactuator controlled valves. The lubrication system 2300 includes a pumpunit 300 having the components described above. The reservoir 304 of thepump unit holds lubricant (e.g., grease) and has reservoir outlet 316for supplying the lubricant to the lubricant delivery system via a lubesupply line 2302 in communication with the cylinder outlet 354 of thepump unit. The pump unit 300 includes the cylinder 334 defining thecylinder bore 338, the cylinder inlet 334 a in communication with thereservoir outlet 316 for flow of lubricant from the reservoir 304 intothe cylinder bore 338, the cylinder outlet 354, and the piston 384movable in the cylinder bore 338 (see FIGS. 3-9). The supply line 2302includes a plurality of valves 2304, each for controlling delivery oflubricant to locations such as bearings 2306 when the valves are openedand the lubricant is under pressure generated by the pump unit 300. Thedrive mechanism of the pump unit (e.g., 326, 390, 1200) including themotor, such as stepper motor 394, reciprocates the piston 384 in thecylinder bore 338 to pressurize the lubricant. A controller 2308, suchas a microprocessor and/or a programmable logic array, controls theoperation of the motor 394 by selectively energizing the motor toreciprocate the piston 384.

A controller area network (CAN) bus 2310, illustrated by dashed lines inFIG. 37, is connected to the controller 2308 and carries CAN commandsignals. It is contemplated that the CAN bus may be implemented as awired or wireless network. As used herein, “connect” means a wired orwireless connection. A power bus 2312 is connected to a power supply2314 to supply power to energize the components of the system 2300, asnoted herein. A plurality of actuators, such as solenoids 2316, isassociated with the valves 2304 for opening and closing respectivevalves. A plurality of CAN modules 2320, each having relays 2318,control operation of the solenoids 2316. For example, each CAN modulemay be model no. EZ221-CO slave interface in combination with model no.EZ500/700 relay unit, both sold by Eaton Corp. The slave interfaceconnects to the CAN Bus 2310 to receive CAN command signals from thecontroller. The relays 2318 are connected to the power bus 2312 forselectively energizing respective actuators 2316 to open and close thevalves 2304 associated with the actuators in order to deliver lubricant.The CAN modules 2320 are connected between the CAN bus 2310 andrespective relays 2318 for controlling respective relays in response toCAN command instructions provided by the controller 2310 via the CAN bus2310.

In one embodiment, a sensor such as a flow meter, a bearing sensor, anacoustic vibration sensor, a heat sensor, and/or a pressure sensor maybe used for sensing a condition related to the system 2300. In general,the sensor may be any sensor which senses lubricant, lubricant flow, alubricant parameter, a lubricant condition, or a need for lubricant. Forexample, an acoustic, thermal, vibration or pressure sensor 2322 may bein communication with bearing 2306A; a pressure sensor 2324 may be incommunication with lube supply line 2302; and/or a flow sensor 2326 maybe in communication with the lube supply line to bearing 2306B. In eachembodiment, the sensor provides a condition signal (e.g., a pressuresignal, a flow signal, a heat signal, a vibration signal) indicative ofthe condition it senses to one of the CAN modules 2320 which provides acorresponding condition signal to the controller 2308 via the CAN bus2310. As a result, the controller is responsive to the correspondingcondition signal to control the motor 394. In one embodiment, thecontroller 2308 is responsive to one or more condition signals to sendCAN signals via the CAN bus 2310 to at least one or more of the CANmodules 2310 to control the CAN relays 2318 associated with the CANmodules 2310 to selectively energize the solenoids 2316 of the CANrelays 2318 associated with the CAN modules to implement a lube event.This results in a lubrication-on-demand type of system. For example, thesensors may be sensing a condition of the system which corresponds to aneed for a lubrication event. In particular, the sensors may be sensinga temperature of a bearing, an acoustic output of a bearing, and/or avibration of a bearing. In response, the controller controls operationof the stepper motor 394 by selectively energizing the motor toreciprocate the piston 384. As a result, the controller 2308 isresponsive to the condition signal to modify system operation such as byselectively energizing the drive mechanism and pump lubricant when thecondition signal is indicative of the need for a lubrication event, suchthat the system provides lubrication on demand.

In one embodiment, one or more alarms 2330 may be part of the system2300. In this embodiment, the controller 2308 includes a memory forstoring alarm conditions and is responsive to the condition signals tomodify system operation such as by selectively energizing the alarm(s)2330 when the condition signal corresponds to one of the alarmconditions. The alarm may be a visual indication, an audible indication,a notice on a screen, an email, a text message, a voice mail message, orany other notification to alert an operator.

In FIG. 37, one or more of the zones may include metering valves (notshown) which are configured to dispense a preset volume of lubricantduring each lubrication event. The divider valves noted herein (see FIG.37A) are an example of metering valves. Depending on the type ofmetering valve, separate actuators (e.g., solenoids 2316) may not or maynot be needed for the valves. For embodiments including a zone havingmetering valves, the controller 2308 is programmed to operate thestepper motor 394 to pump lubricant to load the metering valves in thezone, following which the metering valves dispense metered volumes oflubricant to the bearings 2306. Alternatively, or in addition, one ormore of the zones may include non-metering valves 2304 which are openedand closed by their respective solenoids 2316. Thus, the controllercontrols the non-metering valves in the zone and determines the amountof lubricant dispensed during a lubricant event. For embodimentsincluding a zone of non-metering valves, the controller is programmed tooperate the stepper motor to pump lubricant to dispense a preset volumeof lubricant in the zone. Thus, the pump stepper motor 394 as energizedby the controller determines the amount of lubricant dispensed during alubricant event.

The controller 2308 can be programmed to pump a preset volume oflubricant in a period of time or for a number of pumping strokes. Thus,the controller can control the pump stepper motor to pump a presetvolume based on a period of time of pump stepper motor 394 operation(e.g., preset volume equals minutes of pump stepper motor 394 operationtimes in³/min or preset volume equals minutes of pump stepper motor 394operation times cc/min) in order to dispense the preset volume oflubricant. Alternatively, the controller can control the pump steppermotor 394 to pump a preset volume based on a number of pumping strokes(e.g., volume equals number of piston strokes times the volume of thecylinder bore displaced by the piston movement during each pumpingstroke or volume equals number of strokes times diameter of cylinderbore times the length of each piston stroke) in order to dispense thepreset volume of lubricant. This type of preset volume control isparticularly applicable in lube-on-demand type systems and in dividervalve distribution systems. In one embodiment, a user can enter via theinput device 454 a preset volume of lubricant to be pumped either in amanual mode which is initiated by the user or in an automatic mode whichis executed periodically by the processor for each lube event. Inresponse, the controller energizes the pump motor 394 for a period oftime corresponding to the preset volume. Although this type of presetvolume control does not require sensors such as pressure or volumesensors, it is contemplated that sensors may be used optionally incertain embodiments to confirm that the preset volume of lubricant hasbeen pumped.

For example, in FIG. 19, the controller 450 can send a message to CANmodule 1121 to open zone Z1 by opening the left valve 1118, and then thecontroller 450 can operate the stepper motor 394 of the pump unit 300for a preset period of time or for a preset number of strokes to pump acorresponding preset volume of lubricant to the lubrication points 1134.Alternatively, the controller 450 can send a message to CAN module 1121to open zone Z2 by opening the right valve 1118 and then the controller450 can operate the pump stepper motor for a preset period of time orfor a preset number of strokes to pump a corresponding preset volume oflubricant to the lubrication points 1148A-1148D. Other zones can besimilarly opened for pumping a preset volume of lubricant.

Similarly, in FIG. 16, the controller 450 can send a message to a CANmodule (not shown) to open zone Z1 by opening the left valve 818, andthen the controller 450 can operate the pump for a preset period of timeor for a preset number of strokes to pump a corresponding preset volumeof lubricant to the lubrication points 834. Alternatively, thecontroller 450 can send a message to the CAN module to open zone Z2 byopening the right valve 818 and then the controller 450 can operate thepump stepper motor for a preset period of time or for a preset number ofstrokes to pump a corresponding preset volume of lubricant to thelubrication points 850. Other zones can be similarly opened for pumpinga preset volume of lubricant.

Similarly, in FIG. 17, the controller 450 can send a message to a CANmodule (not shown) to open zone Z1 by opening the left valve 918, andthen the controller 450 can operate the pump for a preset period of timeor for a preset number of strokes to pump a corresponding preset volumeof lubricant to the lubrication points 934. Alternatively, thecontroller 450 can send a message to the CAN module to open zone Z2 byopening the right valve 918 and then the controller 450 can operate thepump stepper motor for a preset period of time or for a preset number ofstrokes to pump a corresponding preset volume of lubricant to thelubrication points 948. Other zones can be similarly opened for pumpinga preset volume of lubricant.

Similarly, in FIG. 18, the controller 450 can send a message to a CANmodule (not shown) to open zone Z1 by opening the left valve 1018 andthen the controller 450 can operate the pump for a preset period of timeor for a preset number of strokes to pump a corresponding preset volumeof lubricant to the lubrication points 1034. Alternatively, thecontroller 450 can send a message to the CAN module to open zone Z2 byopening the right valve 1018 and then the controller 450 can operate thepump stepper motor for a preset period of time or for a preset number ofstrokes to pump a corresponding preset volume of lubricant to thelubrication points 1048. Other zones can be similarly opened for pumpinga preset volume of lubricant.

Similarly, in FIG. 19A, the controller 450 can send a message to a CANmodule (not shown) to open zone Z2 by opening the left valve 1418, andthen the controller 450 can operate the pump for a preset period of timeor for a preset number of strokes to pump a corresponding preset volumeof lubricant to the lubrication points 1482. Alternatively, thecontroller 450 can send a message to the CAN module to open zone Z2 byopening the right valve 1418 and then the controller 450 can operate thepump stepper motor for a preset period of time or for a preset number ofstrokes to pump a corresponding preset volume of lubricant to thelubrication points 1434. Other zones can be similarly opened for pumpinga preset volume of lubricant.

Similarly, in FIG. 19B, the controller 450 can send a message to a CANmodule (not shown) to open zone Z1 by opening the right valve 1418 andthen the controller 450 can operate the pump for a preset period of timeor for a preset number of strokes to pump a corresponding preset volumeof lubricant to the lubrication points 1934. Alternatively, thecontroller 450 can send a message to the CAN module to open zone Z2 byopening the right valve 1418 and then the controller 450 can operate thepump stepper motor for a preset period of time or for a preset number ofstrokes to pump a corresponding preset volume of lubricant to thelubrication points 1482. Other zones can be similarly opened for pumpinga preset volume of lubricant.

The zone of FIGS. 37 and 37A can be similarly opened for pumping apreset volume of lubricant. In addition, since the volume of lubricantbeing dispensed by pump unit is know to the processor, this informationcan be used as diagnostic information. For example, consider a systemwith 100 lubrication points needing a total required volume of 150 cc oflubricant during a lube event. After a lube event is executed, theprocessor can compare the actual dispensed volume of lubricant dispensedduring the lube event to the total required volume. If the actualdispensed volume is less than the total required volume, this wouldindicate a blocked line or other problem preventing lubricant delivery.If the actual dispensed volume is greater than the total requiredvolume, this would indicate a broken line or other problem such as aleak causing lubricant to escape from the system. Thus, the volume oflubricant dispensed can be monitored and an alarm actuated when theactual volume dispensed differs from the total required volume.

Also, the period of time during which a valve is open, as determined bythe controller, can impact the amount of lubricant delivered. In certaininstallations, metered valves (e.g., injectors and/or divider valves)may be more expensive to implement than non-metered valves so that itmay be less expensive to implement zones of non-metered valves. Theflexibility of the system 2300 permits various types of zones in orderto meet the various requirements of a particular installation.

FIG. 37A is a block diagram of one embodiment of a CAN bus lubricationsystem 2301 of the invention for supplying lubricant to zones of dividervalves and zones of injectors (see also FIG. 17 for a similar zoneillustration). It is contemplated that the systems 2300 and 2301 may becombined as one system including one or more zones of injectors, dividervalves and/or actuator controlled valves. System 2301 includes a pumpunit 300. The system also includes a valve 2304M opened and closed bysolenoid 2316M for supplying lubricant to a zone of injectors 2317lubricating bearings 2306M. One of the relays 2318M of the CAN module2320M is selectively closed to energize solenoid 2316M to open valve2304M to supply lubricant via lube supply line 2302 to injectors 2317.Pressure sensor 2347 senses the pressure of the lubricant in the linebetween the valve 2304M and the injectors 2317 and provides a pressuresignal to CAN module 2320M which sends a corresponding signal tocontroller 2308 via CAN bus 2310.

System 2301 also includes a valve 2304N opened and closed by solenoid2316N for supplying lubricant to a zone of divider valves 2340 forlubricating bearings 2342. One of the relays 2318M of the CAN module2320M is selectively closed to energize solenoid 2316N to open valve2304N to supply lubricant via lube supply line 2302 to divider valve2340B, which supplies lubricant to divider valves 2340A, 2340Clubricating bearings 2342. Pressure sensor 2346 senses the pressure ofthe lubricant in the line between the divider valve 2340C and thebearing 2342E and provides a pressure signal to CAN module 2320Q whichsends a corresponding signal to controller 2308 via CAN bus 2310.Pressure sensor 2348 senses the pressure of the lubricant in the linebetween the valve 2340A and the bearing 2342C and provides a pressuresignal to CAN module 2320M which sends a corresponding signal tocontroller 2308 via CAN bus 2310. A proximity switch (PX) 2341associated with divider valve 2340C senses activation of valve 2340C andprovides an activation signal to CAN module 2320Q which sends acorresponding signal to controller 2308 via CAN bus 2310, confirmingactivation of valve 2340C.

As will be appreciated by those skilled in the art, a system of theinvention including a CAN bus and CAN modules can be configured inseveral different forms with several different types of zones. As oneexample, the system may have sensors and operate as a lube-on-demandtype system in response to the sensors. Such a system may or may nothave metering valves in a particular zone. As another example, thesystem may be programmed to execute lubrication events according to aschedule, such as every 15 minutes. Such a system may or may not havemetering valves in a particular zone and may or may not have sensors towhich the controller responds.

Each zone may have a zone valve which is controlled by a zone actuatorresponsive to a CAN zone module. The zone valve selectively supplieslubricant to the zone. For example, as shown in FIG. 19, valves 1118 arezone valves controlling lubricant flow to zones Z1, Z2, and the CANmodules 1121, 1123 are CAN zone modules for controlling zone actuatorsassociated with respective zone valves 1118 for opening and closing thevalves 1118.

The zones may include one or more sensors, such as line pressure sensors2346, 2347, 2348 for sensing the pressure of lubricant in one or moresupply lines and/or one or more proximity switches 2354 for sensing aset/reset condition of one or more divider valves 2340B.

The following are examples of various sensors which may be part of thesystem 2300. The sensors send condition signals to the controller for anappropriate response by the controller.

A pressure sensor may be used to monitor a lubricant pressure of thelubricant delivery system. In this example, the condition signal is apressure signal and the controller is responsive to the pressure signalto energize an alarm when the pressure signal indicates that thelubricant pressure is less than a minimum pressure setting (e.g., see1574 and 1578 of the ventmeter test, FIG. 23, which activate an alarm.)

A pressure sensor may be used to monitor a lubricant pressure at thecylinder outlet of the pump unit 300. In this example, the conditionsignal is a pressure signal and the controller is responsive to thepressure signal to energize an alarm when the pressure signal indicatesthat the lubricant pressure at the pump is greater than a maximumpressure setting (e.g., see maximum pump pressure; FIG. 24).

A motion sensor may be used to monitor a movement of the piston of thepump unit 300. In this example, the condition signal is a motion signaland the controller is responsive to the motion signal to energize analarm when the motion signal indicates that the piston movement is lessthan a minimum movement (e.g., see full-stroke test; FIG. 25) (No alarmin FIG. 25).

A level sensor may be used to monitor a lubricant level of the reservoirof the pump unit 300. In this example, the condition signal is a levelsignal and the controller is responsive to the level signal to energizean alarm when the level signal indicates that the lubricant level isless than a minimum level (e.g., see reservoir level test; FIG. 26).

A pressure sensor may be used to monitor a lubricant pressure in a lubeline and/or at a lube point in the lubricant delivery system. As notedherein, the pressure sensor may bean internal (pump) PT and anend-of-line PT. In this example, the condition signal is a pressuresignal and the controller is responsive to the pressure signal toenergize an alarm when the pressure signal indicates that the lubricantpressure is less than a minimum pressure setting after a given period oftime of pump motor operation has elapsed (e.g., see cycle (i.e.,injector reset) time out test; FIG. 27).

In one embodiment (FIG. 37A), the controller 2308 selectively energizesthe stepper motor 394 and a current sensor 2360 monitors a currentapplied to the stepper motor 394. In this example, the condition signalis a current signal and the controller is responsive to the currentsignal to energize an alarm when the current signal indicates that thecurrent applied to the stepper motor is greater than a maximum currentsetting. Alternatively or in addition, as noted herein, the steppermotor current is monitored in order to selectively overdrive the steppermotor. Alternatively or in addition, as noted herein, the stepper motorcurrent is monitored as an indication of the internal (pump) pressure.

In some embodiments, a stirrer 320 in the reservoir is driven by astirrer motor 326 to mix the lubricant and keep it fluid by reducing itsviscosity. In this embodiment, the controller 2308 selectively energizesthe stirrer motor and a current sensor 2358 monitors a current appliedto the stirrer motor 326. In this example, the condition signal is acurrent signal and the controller is responsive to the current signal toenergize an alarm when the current signal indicates that the currentapplied to the stirrer motor 326 is greater than a maximum currentsetting (e.g., see lubricant reservoir stiffness test; FIG. 28).

As noted herein, the controller may a processor in which case it wouldinclude a tangible, computer readable non-transitory storage mediumincluding processor executable instructions for controlling theoperation of the processor. In this embodiment, the processor programmedby an operator to execute one or more of the following sets ofinstructions:

-   -   (i) instructions for determining whether a lubricant injector        connected to the system is venting and for energizing an alarm        when the ventmeter test indicates that the injector is not        venting;    -   (ii) instructions for determining a lubricant pressure at the        cylinder outlet of the pump unit and for energizing an alarm        when the determined pressure is greater than a maximum pressure;    -   (iii) instructions for determining a piston movement and for        energizing an alarm when the determined piston movement is less        than a minimum movement;    -   (iv) instructions for determining a lubricant level of the        reservoir and for energizing an alarm when the determined        lubricant level is less than a minimum level; and/or    -   (v) instructions for determining a lubricant pressure and for        energizing an alarm when the determined pressure is less than a        maximum pressure after a given period of time of motor pump        operation has elapsed.

The controller area network (CAN) bus 2310 system and features describedabove have been described in the context of lubrication systems whichinclude the pump unit 300 described earlier. However, it will beunderstood that these same self-diagnostic features can be used inlubrication systems having other pump units, such as the pump units2500, 2900 described below and other lubricant pump units that include astepper motor or an alternative linear position drive mechanism (e.g.,the mechanism of FIG. 20 or FIG. 21).

Similarly, the self-diagnostic features described above have beendescribed in the context of lubrication systems which include the pumpunit 300 described earlier. However, it will be understood that thesesame self-diagnostic features can be used in lubrication systems havingother pump units, such as the pump units 2500, 2900 described below andother lubricant pump units that include a stepper motor or analternative linear position drive mechanism (e.g., the mechanism of FIG.20 or FIG. 21).

FIGS. 38-54 illustrate another embodiment of a pump unit of thisinvention, generally designated 2500. The pump unit is similar to thepump unit 300 described above. It comprises a reservoir 2504 for holdinga supply of lubricant (e.g., grease) and a pump housing 2506 below thereservoir for housing various pump components of the unit, including apump cylinder 2508 and a piston 2512 movable back and forth in thecylinder (see FIGS. 41 and 42).

Referring to FIGS. 38 and 39, the reservoir 2504 comprises a tank 2518having a side wall 2520, a removable top 2526, and no bottom wall. Thelower end of the side wall 2520 rests on the pump housing 2506. A numberof tie rods 2530 connect the cover 2526 to the pump housing 2506 andhold the tank in place on the housing. The cover 2526 can be removed byunthreading nuts 2532 on the tie rods 2530. The tank 2518 has aninterior 2536 for holding a supply of lubricant (e.g., grease). Aspring-loaded follower 2538 mounted on a central vertical shaft 1939 inthe tank 2518 bears against the grease and wipes against the insidesurface of the tank as the level of grease falls during operation of thepump unit 2500.

Referring to FIGS. 39 and 401, the pump housing 2506 comprises a topwall 2540, a side wall 2542 forming a skirt depending from the top wall,and bottom wall 2546. A collar 2548 extends up from the top wall 2540and is sized for receiving the lower end of the reservoir tank 2518. Aseal 2550 on the collar 2548 seals against the side wall 2520 of thetank to prevent leakage. A refill port 2554 is provided on the housing2506 for refilling the tank 2518 with lubricant. A refill conduit 2556connects the refill port 2554 to an outlet 2560 opening in the top wall2540 of the housing. The outlet opening 2560 communicates with theinterior 2536 of the tank 2518 for flow of lubricant into the tank torefill it. In a dual line system, the refill port 2554 is connected tothe return line to provide access to the tank 2518 and to supply to thetank the lubricant provided by the return line.

The pump cylinder 2508 is mounted in the pump housing 2506 immediatelybelow the top wall 2540 of the housing. As shown in FIGS. 41 and 42, thepump cylinder comprises a cylinder body 2562 and a valve housing 2564 inthreaded engagement with the cylinder body. The cylinder body 2562 isillustrated as being of two-piece construction, but it may comprise anynumber of parts. The cylinder body 2562 and valve housing 2564 haveco-axial longitudinal bores indicated at 2566A and 2566B, respectively,forming a longitudinal cylinder bore 2566. The piston reciprocates inthe bore 2566A which, in this embodiment, has a diameter D1. The bore2566B in the valve housing 2564 has multiple diameters to accommodatevarious check valve components, as will be described later.

The cylinder body 2562 has an inlet comprising an inlet passage 2570extending from a face 2572 of the body to the cylinder bore 2566. Theface 2574 is in sealing engagement (via seal 2576 in FIG. 43) with anopposing face 2578 of the top wall 2548 of the pump housing 2506. Thetop wall 2548 of the pump housing has an opening 2582 aligned with theinlet passage 2570 to form a defined tunnel-like flow path 2586 from theinterior 2536 of the tank 2518 to the cylinder bore 2566. The flow path2586 is closed along its entire length from the interior of the tank2536 to the cylinder bore 2566. Desirably, the flow path 2586 is agenerally straight-line path which extends generally vertically from anupper end of the flow path to a lower end of the flow path. Alsodesirably, the total length of the defined flow path 2586 is relativelyshort (e.g., less than four inches; preferably less than three inches,and even more preferably less than two inches).

Referring to FIG. 43, the opening 2582 in the top wall 2548 of the pumphousing 2506 is generally conical and defines an outlet of a tank 2518.The opening 2582 has a large-diameter upper end to facilitate flow oflubricant from the tank 2518 into the opening and a smaller-diameterlower end. The tapered opening 2582 funnels lubricant into the inletpassage 2570 of the cylinder 2508. The opening 2582 has an upper enddiameter D2, a lower end diameter D3, and an axial length L1.

The cylinder inlet passage 2570 has an upper portion 2570A that issubstantially cylindrical (with a small taper to facilitate manufacture)and co-axial with the opening 2582 in the top wall 2548 of the housing2506. The upper portion 2570A has a diameter D4 and an axial length L2.The inlet passage 2570 also has a lower portion 2570B that is oblong(e.g., racetrack) as viewed in horizontal cross-section (see FIGS. 44and 45). The oblong portion 2570B has a major dimension D5 takengenerally transverse to the longitudinal centerline 2588 of the cylinderbore that is about equal to the full diameter D1 of the cylinder bore2566 at the juncture of the inlet passage 2570 and the cylinder bore, ashorter minor dimension D6 generally parallel to the longitudinalcenterline of the cylinder bore that is less than the full diameter ofthe cylinder bore 2566A, and a length L3. The oblong configurationmaximizes the area of flow into the cylinder bore 2566 and reduces theeffective length of the piston power stroke, i.e., the segment of thepower stroke after the piston 2512 has moved past the cylinder inletpassage 2570 and blocked communication between the cylinder bore 2566and the inlet passage. As a result, the pump unit 2500 has a morecompact design while still pumping a relatively large volume oflubricant (e.g., at least 1.5 cubic centimeters) per pumping stroke ofthe piston.

Exemplary dimensions are given below. They are exemplary only.

-   -   D1—0.435 in.    -   D2—1.033 in.    -   D3—0.500 in.    -   D4—0.440 in.    -   D5—0.435 in.    -   D6—0.187 in.    -   L1—0.590 in.    -   L2—0.840 in.    -   L3—1.125 in.    -   L4—0.425 in. (slot interior).

The defined flow path 2586 may have other configurations in which thepath is formed by a tunnel-like passage having an open upper end forentry of lubricant from the interior 2536 of the tank 2518 directly intothe passage, and an open lower end for exit of lubricant from thepassage directly into the cylinder bore 2566. The defined flow path canbe formed by any number of separate passage-forming members (e.g., thetop wall 2548 of the pump housing 2506 and the cylinder body 2562)having aligned openings that combine to form a closed tunnel-likepassage that is closed except at one end for entry of lubricant from theinterior of the tank directly into the passage and at an opposite endfor exit of lubricant from the passage directly into the cylinder bore2566.

Referring to FIGS. 45-47, a stirrer, generally designated 2600, isprovided for stirring lubricant in the tank 2518. The stirrer 2600comprises a rotary hub 2602 rotatable about a vertical axis 2604 by afirst drive mechanism 2606 in the pump housing 2506. An arm 2610 extendsgenerally horizontally outward in a radial direction from the hub 2602adjacent the bottom of the tank 2518. An upstanding stirring member 2614at the outer end of the arm 2610 extends up alongside the cylindricalside wall 2520 of the tank 2518. Rotation of the stirrer 2600 fluidizeslubricant in the tank and breaks up any air bubbles that may be in thelubricant to minimize the risk that the pump unit 2500 will lose itsprime.

Referring to FIG. 46, the stirrer drive mechanism 2606 comprises anelectric motor 2616 and a transmission 2618 connecting the output shaft2620 of the motor to the hub 2602 of the stirrer 2600. Rotation of theoutput shaft 2620 acts through the transmission 2618 to rotate thestirrer 2600 about the vertical axis 2604 at a suitable speed (e.g.,40-60 rpm.) The stirrer hub 2602 is affixed to an output 2624 shaft ofthe transmission by suitable means (e.g., a setscrew) so that the hubrotates in unison with the output shaft. A spacer 2626 at the upper endof the stirrer hub 2602 supports the lower end of the follower shaft2539. The spacer 2626 is affixed to the stirrer hub by suitable means(e.g., a setscrew) so that it rotates in unison with the stirrer hub.The lower end of the follower shaft 2539 is received in an opening 2628in the upper end of the spacer 2626 and remains stationary as the spacerrotates with the hub 2602.

The stirrer 2600 includes a force-feed mechanism 2630 operable onrotation of the stirrer to force lubricant under pressure from the tankthrough the tank outlet, i.e., through opening 2582. As illustrated inFIGS. 46 and 47, the force-feed mechanism 2630 comprises a force-feedmember 2632 on the arm 2610 of the stirrer. The force-feed member 2632extends along the arm and has a downwardly inclined lower surface 2636that lies in a plane oriented an angle 2648 relative to the top wall2540 of the forming, in essence, the bottom of the reservoir. Theforce-feed member 2632 terminates at a lower end 2638 spaced arelatively small distance (e.g., 0.16 in.) above the wall 2540. Rotationof the stirrer 2600 causes the angled force-feed member 2632 to movethrough the lubricant and to generate a pushing force tending to pushlubricant down through the opening 2582 in the top wall 2540 of the pumphousing 2506 and along the defined flow path 2570 to the cylinder bore2566.

The downward pushing force exerted on the lubricant by the force-feedmechanism 2630 is complemented by a pulling force exerted on thelubricant by the piston 2512 of the pump as it moves through a returnstroke. It will be understood in this regard that movement of the piston2512 through a return stroke generates a reduced pressure in thecylinder bore 2566 that tends to pull lubricant down along the flow path2570 toward the cylinder bore. Desirably, the controller of the pumpunit 2500 is programmed to operate the stirrer 2600 and the piston 2512simultaneously so that the pushing and pulling forces act simultaneously(in concert) to move lubricant along the defined flow path 2570 into thecylinder bore 2566. When combined, these forces are able to movelubricant more forcefully from the reservoir to the cylinder bore.Further, these forces are maximized because the flow path 2570 from theinterior of the tank 2536 to the cylinder bore 2566 is closed toatmosphere along its entire length. As a result, the pump unit 2500 isable to pump more viscous lubricants at lower temperatures thanconventional pump units.

The benefit of the push-pull arrangement described above is illustratedin the graph of FIG. 48 comparing the results of tests conducted using astate-of-the art pump sold by Lincoln Industrial (model 653) and a pumpunit having the configuration of pump unit 2500 described above. Thelubricant used in the test was a Lithium Moly NLGI 2 Grade grease havinga yield stress of 800 psi as measured using the ventmeter test describedabove and in U.S. Pat. No. 7,980,118 incorporated by reference herein.(The National Lubrication Grease Institute (NLGI) defines standarddesignations for grease stiffness.) As shown by the graph, the“push/pull” forces exerted by the pump unit of our new design is capableof pumping grease at substantially lower temperatures (at least 15degrees lower) than the state-of-the art design.

Referring to FIG. 42, a first ball check valve 2670 is mounted in thevalve housing 2564 for movement in bore 2566B between a closed positionin which it engages a first valve seat 2672 on the housing to block flowthrough the cylinder bore 2566 during a return stroke of the piston 2512and an open position in which it allows flow through the bore during apumping stroke of the piston. A first coil compression spring 2676reacting at one end against the ball valve 2670 urges the ball valvetoward its closed position. The opposite end of the spring 2676 reactsagainst a second ball check valve 2678 downstream from the first ballvalve 2670. The second ball valve 2678 is mounted in the valve housing2564 for movement in bore 2566B between a closed position in which itengages a second valve seat 2680 on the housing to block flow throughthe cylinder bore 2566 during a return stroke of the piston 2512 and anopen position in which it allows flow through the bore during a pumpingstroke of the piston. A second coil compression spring 2682 reacting atone end against the second ball valve 2678 urges the ball valve towardits closed position. The opposite end of the spring 2682 reacts againsta plug 2684 threaded into the downstream end of the bore 2566B. The useof two check valves 2670, 2678 instead of only one check valve (as inthe first embodiment described above) reduces the risk of back flow oflubricant into the inlet part 2508A of the cylinder during a returnstroke of the piston.

Referring to FIGS. 49 and 50, the pump cylinder 2508 has an outletcomprising an outlet port 2700 in the cylinder body 2562. The outletport 2700 communicates with the cylinder bore 2566 via an annular gap2702 located between the valve housing 2564 and the cylinder body 2562and via a connecting passage 2704 extending between the annular gap andthe bore 2566B in the valve housing at a location downstream from thesecond ball check valve seat 2680. A lubricant outlet fitting 2708 isthreaded into the outlet port 2702. In the illustrated embodiment, theoutlet fitting 2708 a T-fitting for flow of lubricant to a first feedline 2714 attached to the pump housing 2506 at one location and to asecond feed line 2716 attached to the pump housing at a second locationspaced around the housing from the first location. The outlet end ofeach feed line 2714, 2716 is equipped with a self-sealing quickconnect/disconnect connector 2720 to facilitate connection of the feedline to a lube supply line supplying lubricant to a distribution systemof one kind of another. In general, only one of the two feed lines isused for any given distribution system, the feed line selected for usebeing the most suitable configuration for conditions in the field.However, both feed lines may be used in some installations.

Again referring to FIGS. 49 and 50, the cylinder body 2562A also has asensor port 2724 that communicates with the bore 2566B by means of theannular gap 2702 and the connecting passage 2704. A pressure sensor 2726threaded in the sensor port senses the pressure at the outlet end of thecylinder bore 2566.

As shown in FIG. 42, a vent passage 2730 in the cylinder body 2562provides fluid communication between a first location in thelongitudinal cylinder bore 2566A upstream from the first check valveseat 2672 and a second location in the longitudinal cylinder bore 2566Bdownstream from the second check valve seat 2680. The downstream end ofthe vent passage 2730 communicates with the second location via theoutlet port 2700, the annular gap 2702, and the connecting passage 2704.The purpose of the vent passage 2730 is identical to the vent passage376 described in the first embodiment. Other vent passage configurationsare possible.

Referring to FIGS. 51-54, the piston 2512 of the pump unit 2500comprises a hollow cylindrical piston body 2720 having a front (right)end and a back (left) end. The body 2720 has internal threads 2722extending from generally adjacent the back of the body toward the frontend of the body but desirably terminating well short of the front end.The front end of the piston body 1222 is closed by a piston head 2726with a circumferential seal 2728 that seals against the inside surfaceof the body.

The piston 2512 is movable in a reciprocating manner in the cylinderbore 2566 by a second drive mechanism, generally designated 2740. In theembodiment of FIGS. 51-54, the drive mechanism 2740 is a linear positiondrive mechanism comprising a stepper motor 2742 having an output shaft2744 connected to a co-axial lead screw 2746 rotatable in a sleevebearing 2750 in an end wall 2752 of a follower housing 2756. The leadscrew 2746 comprises a lead screw body 2760 having a blind bore 2762that receives the output shaft 2744 of the stepper motor 2742, and athreaded shaft 2766 extending forward from the body. The shaft 2766 hasexternal threads 2768 configured to mate with the internal threads 2722of the piston body 2720. The stepper motor output shaft 2744 is keyed at2770 to the body 2760 of the lead screw so that the shaft and lead screwturn in unison. Desirably, the mating threads on the piston and leadscrew are constructed for the efficient transmission of power. By way ofexample, the threads 2722, 2768 may be full ACME threads capable ofcarrying a substantial load for pumping lubricant at high pressures.

Thrust loads exerted on the piston 2512 and lead screw 2746 are carriedby first and second thrust bearings 2774, 2776 on opposite sides of theend wall 2752 of the follower housing 2756. The first thrust bearing2774 supports axial loads in the rearward direction (i.e., toward theleft as viewed in FIG. 51) during a pumping stroke of the piston 2512 asit moves forward in the cylinder bore 2566A. The thrust bearing 2774comprises a needle bearing 2780 and two bearing races 2782 held captivebetween the follower housing end wall 2752 and a peripheral radialflange 2784 on the lead screw body 2760. The second thrust bearing 2776supports axial loads in the forward direction (i.e., toward the right asviewed in FIG. 51) during a return stroke of the 2512 piston as it movesrearward in the cylinder bore 2566A. The thrust bearing 2776 comprises aneedle bearing 2786 and two bearing races 2788 held captive between thefollower housing end wall 2752 and a retaining ring 2790 on the leadscrew. A seal 2792 in a counterbore in the follower end wall 2752immediately forward of the second thrust bearing 2776 seals against thelead screw body 2760 to prevent leakage.

A follower 2800 is secured to the piston 2512 for back and forth linear(non-rotational) movement of the follower and piston in a cavity 2802 inthe follower housing 2756. The cavity 2802 extends forward from the endwall 2752 of the housing 2756, located generally adjacent the back endof the housing, to the front end of the follower housing. In thisembodiment, the longitudinal centerline of the cavity 2802 is generallyco-axial with the longitudinal centerlines of the piston 2512 and leadscrew 2746. The front end of the follower housing 2750 seals against theback end of the cylinder body 2562 such that the longitudinal centerlineof the cavity 2802 is generally co-axial with the longitudinalcenterline of the cylinder bore 2566 and such that the piston 2512extends from the follower cavity into the cylinder bore forreciprocation in the cylinder bore 2566A.

As illustrated in FIG. 53, the follower 2800 comprises a circularfollower body 2806 having a central bore 2808 with a larger-diameterrear portion 2808A that receives the peripheral flange 2784 on the leadscrew body 2760 and part of the first thrust bearing 2774, and asmaller-diameter forward portion 2808B that receives a back end portionof the piston body 2720. The smaller-diameter portion 2808B of thefollower bore 2808 and the back end portion of the piston body 2720 arenon-circular in shape (e.g., rectangular) to prevent relative rotationalmovement between the piston and the follower. Relative axial movementbetween the two parts is prevented by an inward-projecting peripheralflange 2812 on the follower body 2806 held captive between anoutward-projecting peripheral flange 2814 on the piston body and aretaining clip 2820 on the piston body. Other constructions are possibleto prevent relative rotation and linear movement between the piston 2512and follower 2800.

As illustrated in FIG. 54, the follower body 2806 has notches 2824 forreceiving stationary linear guides defined by rails 2826 on the insideof the follower housing 2756. The rails 2826 extend in a directiongenerally parallel to the longitudinal cylinder bore 2566 and hold thefollower 2800 (and piston 2512) against rotation as the lead screw 2746is rotated by the stepper motor 2742. As a result, rotation of the motoroutput shaft 2744 and lead screw 2746 in one direction causes the piston2512 to move linearly in the cylinder bore 2566A through a pumpingstroke, and rotation of the output shaft 2744 and lead screw 2746 in theopposite direction causes the piston to move linearly in the cylinderbore through a return stroke. The lengths of the pumping and returnstrokes are controlled by operation of the stepper motor 2742 undercontrol of the controller.

Desirably, the cavity 2802 functions as a reservoir for holding alubricant (e.g., oil) suitable for lubricating the threads 2722, 2768 onthe lead screw 2746 and the piston 2512. Further, an oil-deliverymechanism is provided for delivering oil from the reservoir to thethreads. In the illustrated embodiment, the oil-delivery mechanismcomprises a portion of the lead screw 2746 comprising the flange 2784 onthe lead screw body 2760. The flange 2784 is sized for immersion in theoil in the reservoir 2802. As the screw 2746 rotates, the flange 2784carries oil up from the reservoir to a location above the lead screw,where the oil flows down a front face of the flange 2784 through a gap2830 between the flange and the back end of the piston body 2720 fordelivery to the threads on the threaded shaft of the lead screw. Notches2834 are provided in the peripheral edge of the flange 2784 to increasethe amount of fluid carried by the flange. In this embodiment, twodiametrically opposed, generally U-shaped notches 2834 are provided, butthe number and shape of the notches may vary. Other oil-deliverymechanisms can be used.

An oil-return mechanism is provided for allowing excess oil delivered tothe mating threads 2722, 2766 on the piston body 2720 and lead screwshaft 2766 to return to the reservoir 2802. In the illustratedembodiment, the oil-return mechanism comprises an axial groove 2840extending along the exterior of the threaded shaft 2766 of the leadscrew. Any excess oil on the shaft 2766 moves along the groove 2840 fordelivery back to the reservoir 2802 through the gap 2830 between thefront face of the lead screw flange 2784 (at the front of the lead screwbody 2760) and the back end of the piston body 2720. A passage 2844extending longitudinally through the follower body 2806 allows lubricantin the reservoir 2802 to flow past the follower 2800 as the follower andpiston move back and forth in the cavity.

Referring to FIG. 44, the follower housing 2756 has an inlet passage2850 for flow of oil from a suitable supply into the cavity. The inletpassage can also be used to drain oil from the cavity.

A calibration mechanism generally designated 2860 in FIG. 51 is providedfor calibrating operation of the stepper motor 2742 relative to theposition of the piston 2512 in the cylinder bore 2566. In theillustrated embodiment, this mechanism 2860 comprises a magnet 2862 onthe follower 2800 movable with the piston 2512, and at least one anddesirably two magnetic field sensors 2864, 2866 mounted on the followerhousing 2756 at spaced-apart locations with respect to the direction ofpiston movement. The controller of the pump unit 2500 receives signalsfrom the calibration mechanism 2860 and calibrates operation of thelinear position drive mechanism 2740 relative to the position of thepiston 2512 in the cylinder 2508.

Other linear position drive mechanisms can be used to reciprocate thepiston 2512 in the cylinder bore 2566. Examples of alternative drivemechanisms are illustrated in FIGS. 20 and 21 and described above.

The operation of the pump unit 2500 is essentially the same as the pumpunit 300 described above. The controller of the pump unit 2500 includesa programmable microprocessor that processes information. The controllercalibrates and controls the operation of the linear position drivemechanism 2740 and is responsive to signals received from the pressuresensor 2726 and the calibration mechanism 2860 (e.g., magnetic fieldsensors 2864, 2866). The controller also controls operation of thestirrer motor 2606 and the stepper motor 2742. Desirably, the controllerinitiates operation of the stirrer motor 2606 before the stepper motor2742 is operated to reciprocate the piston 2512. This sequence allowsthe stirrer 2600 to fluidize the lubricant and prime the pump cylinder2508 with lubricant before the actual pumping of lubricant begins, whichcan be especially advantageous if the lubricant is in a viscouscondition, as in cold-temperature environments. After a suitable delayof predetermined length (e.g., eight-twelve seconds), the stepper motor2742 is energized to move the piston 2512 through a succession of one ormore pumping and return strokes to pump the desired amount of lubricantthrough the feed line 2714, 2716 connected to the distribution lubesupply line.

When the pump unit 2500 is operated in a non-venting mode, the piston2512 moves forward in the cylinder bore 2566 through a pumping stroke topump lubricant from the cylinder bore 2566 and rearward through anon-venting return stroke during which the piston stops short of thelocation at which the vent passage 2730 communicates with the cylinderbore 2566A. That is, the limit of the return stroke is downstream fromthe location at which the vent passage 2730 communicates with thecylinder bore 2566A. As a result, the vent passage 2730 does notcommunicate with the interior 2536 of the tank 2518, and there is noventing of the distribution system during a return stroke of the piston.As explained earlier, such venting is unnecessary in a progressive(divider) valve distribution application.

If the pump unit 2500 is used with an injector distribution systemrequiring venting, the controller of the pump unit is programmed tooperate the unit to pump the desired amount of lubricant through a lubesupply line to a plurality of injectors at desired intervals of time.The injectors operate to deliver metered amounts of lubricant torespective points of lubrication (e.g., bearings). In this mode, thepump unit 2500 operates as described above except that the piston 2512moves forward in the cylinder bore 2566 through a pumping stroke to pumplubricant from the cylinder bore 2566 and rearward through a ventingreturn stroke during which the piston moves past the location at whichthe vent passage 2730 communicates with the cylinder bore 2566A. Thatis, the limit of the return stroke is upstream from the location atwhich the vent passage 2730 communicates with the cylinder bore 2566A.As a result, the vent passage 2730 communicates with the interior of thetank (via the cylinder bore 2566A and the defined flow path 2586), andlubricant is vented to the tank to allow the injectors to reset for thenext lube event.

Thus, the piston 2512 of the pump unit 2500 is movable through bothventing and non-venting return strokes, depending on whether thedistribution system being supplied with lubricant by the pump unitrequires venting between lubrication events. In the embodiment describedabove, a venting return stroke of the piston 2512 is somewhat longerthan a non-venting return stoke of the piston.

The pump unit 2500 is capable of pumping viscous lubricants atrelatively low temperatures. This is due, at least in part, by thestrong push/pull forces exerted on the lubricant to force lubricant fromthe reservoir directly into the cylinder bore 2566. As explained above,rotation of stirrer 2600 causes the force-feed mechanism 2630 to exert astrong downward force on lubricant in the interior 2536 of the tank 2518tending to push it along the defined flow path 2586 to the cylinder bore2566A. Further, a return stroke of the piston generates a force tendingto pull this same lubricant along the same defined flow path 2586. Thecombination of these pushing and pulling forces is effective for movingviscous lubricant into the cylinder bore at lower temperatures.

The use of a stirrer and force feed mechanism of the type describedabove is not limited to the pump unit 300 and the pump unit 2500. Thestirrer and force feed mechanism can be used in any type of pump unit inwhich lubricant is fed along a defined flow path from a reservoir to aninlet of a cylinder in which a piston reciprocates to deliver lubricantto a lubrication distribution system. The piston can be reciprocated byany type of linear or non-linear drive mechanism.

Further, the feature of moving a piston in a cylinder through forwardpumping strokes and through rearward venting and non-venting returnstrokes of different lengths can be employed in lubricant pump unitsother than pump units 300 and 2500. The piston can be reciprocatedthrough such strokes by any type of linear or non-linear drive mechanismto pump lubricant to vented (e.g., injector) lubricant distributionsystems and to non-vented (e.g., divider valve) lubricant distributionsystems.

In other embodiments, the tank 2518 of the reservoir 2504 may have abottom wall that overlies the top wall 2540 of the pump housing 2506. Insuch embodiments, the tank bottom wall has an outlet opening for exit oflubricant from the tank. Desirably, this outlet opening forms part of adefined flow path from the interior of the tank to the cylinder bore.One such embodiment is described below.

FIGS. 55A, 55B, 55C, and 55D illustrate apparatus for supplyinglubricant, generally designated by 2900, that is very similar to thepump unit 2500 described above in FIGS. 38-54. The apparatus 2900comprises a pump assembly including a pump housing 2902 and a lubricantpump, generally designated 2906, in the housing for pumping lubricant toone or more lubrication sites. The pump 2906 comprises componentssimilar to those in the pump unit 2500 described above, including apiston 2908 movable in a cylinder bore 2910 by a linear drive mechanism2912 (e.g., a stepper motor 2914 and follower 2916 of the type describedabove in FIGS. 38-54), an inlet 2920 communicating with the cylinderbore for receiving lubricant, and an outlet 2924 communicating with thecylinder bore for discharging lubricant at a pressure higher than thatof the lubricant at the inlet. In general, the pump 2906 operates in thesame manner described above regarding pump unit 2500.

The apparatus also includes a reservoir 2930 comprising a tank 2932sized for holding a volume of lubricant. The tank has a side wall 2936and a removable top 2938. The side wall 2936 of the tank sits on thepump housing 2902. The reservoir also includes a stirrer, generallydesignated 2940, for stirring lubricant in the tank 2932, and aspring-biased follower 2942 in the tank that bears against the lubricant(e.g., grease) and wipes against the inside surface of the side wall2936 of the tank as the level of grease falls during operation of thepump unit 2900. The stirrer 2940 and follower 2942 may be similar inconstruction and operation to the stirrer 2600 and follower 2538described above in pump unit 2500.

The pump housing 2902 has a top wall 2950 and a side wall 2952. The topwall 2950 has an opening 2954 forming an outlet of the tank. The opening2954 is positioned above the inlet 2920 of the pump 2906 for delivery oflubricant from the interior of the tank 2932 to the cylinder bore 2910along a defined flow path of the type describe above in regard to theembodiment of FIGS. 38-54.

A temperature sensor 2956 is mounted on a boss formed on a lower face2958 of the top wall 2950. A heater 2960 (e.g., a 100 watt cartridgeresistance heater) is also mounted inside the pump housing. In theillustrated embodiment, the heater 2960 is mounted on the lower face2958 of the top wall 2950. By way of example but not limitation, theheater 2960 comprises a 100-watt cartridge resistance heater for raisingthe temperature of the lubricant in the tank 2932 about 10° F.-15° F.Although the heater 2960 may be mounted to the lower face 2958 of thetop wall 2950 by other means, in one embodiment, the heater is fastenedto the top wall with a conventional tubing clamp 2962. Similarly, thesensor 2956 may also be fastened to the top wall 2950 with aconventional tubing clamp 2964.

The temperature sensor 2956 includes leads 2970 that are connected to acontrol or processor such as described previously. The heater 2960 maybe energized before start up or upon receiving a signal from thetemperature sensor 2956 indicating a temperature less than apredetermined minimum temperature (e.g., 20° F.). Desirably, the pumphousing 2902 is made from a thermally conductive material such asaluminum, and the bottom of the reservoir tank (defined in thisembodiment by the top wall 2950 of the pump housing 2902) is made of athermally conductive material such as aluminum so that heat energyprovided by the heater 2960 heats lubricant in the reservoir to maintainthe lubricant at a suitable stiffness for pumping. As other features ofthe pump unit 2900 are similar to those previously described, they willnot be described in further detail. As controls for energizing heatersare well known in the art, they need not be described in further detail.

Optionally, the tank 2932 may have a bottom wall (2978, FIG. 55E)separate from and overlying the top wall 2950 of the pump housing 2902,creating an interface between an upper face 2980 of the top wall 2950 ofthe housing and a lower face 2982 of the bottom wall 2982 of the tank.To promote thermal conduction across this interface, the opposing facesare preferably contoured, sized, and shaped for face-to-face contactwith each other. In one embodiment, the faces opposing are planar toensure face-to-face contact. By way of example, the area of the lowerface 2982 of the bottom wall 2978 of the reservoir tank 2930 in contactwith the upper face 2980 of the top wall 2950 of the pump housing 2902may represent at least 70%, or at least 75%, or at least 80%, of theoverall surface area of the lower face of the bottom wall of the tank.

As noted above regarding FIG. 28, the self-diagnostics of the processormay energize heater 2910 in response to the reservoir lubricant beingtoo stiff as determined by the reservoir-lubricant stiffness test ofFIG. 28. Alternatively or in addition, the processor may be connected toa temperature sensor providing an indication of the ambient temperatureof the lubrication system and the heater may be energized by theprocessor in response to the sensed ambient temperature. For example,depending on the type of lubricant, the heater may be energized when thesensed ambient temperature is below a user setting (e.g., 40° F.).Alternatively or in addition, the processor may be connected to atemperature sensor providing an indication of the temperature of thelubricant and the heater may be energized by the processor in responseto the sensed lubricant temperature. In this embodiment the sensor maybe positioned within the lubricant for sensing the temperature of thelubricant itself or the sensor may be positioned adjacent a component ofthe pump unit (e.g., the pump housing on which the reservoir is seated)for sensing a temperature indicative of the lubricant temperature.

The heater feature described above is described in the context of aspecific lubricant pump unit 2900. However, it will be understood thatthis same feature can be used in other lubricant pump units having alubricant reservoir of thermally conductive material seated on a pumphousing of thermally conductive material, regardless of the type of pumpdrive mechanism.

There are several ways to program the main controller 450 to control amotor driver circuit 451 for driving the stepper motor 394 to turn thelead screw 410 to cause the piston 384 to reciprocate and pumplubricant. For example, in one embodiment the controller 450 may beprogrammed to cause the motor drive circuit 451 to rotate the motorshaft 396 clockwise for a preset period of time and then to rotate themotor shaft 396 counterclockwise for a preset period of time. In anotherembodiment, the controller 450 may be programmed to cause the motordrive circuit 451 to rotate the motor shaft 396 clockwise for a presetnumber of revolutions and then to rotate the motor shaft 396counterclockwise for a preset number of revolutions.

In another embodiment, magnetic field sensors 440, 442 such as reedswitches or Hall sensors may be positioned at or near the ends of thecylinder bore 338 or at or near the ends of the pumping stroke forsensing the position of the piston or the follower. A magnet 434 may beapplied to the piston 384 or the follower 414 to indicate the pistonposition and for sensing by the sensors. In this embodiment, the maincontroller 450 would be responsive to the sensors to reciprocate thepiston. In particular, the controller 450 may be programmed to cause themotor drive circuit 451 to rotate the motor shaft 396 clockwise untilthe switches/sensors indicate that the position of piston is at or nearone end of the cylinder bore 338 (at one end of the pumping stroke) andthen to rotate the motor shaft 396 counterclockwise until theswitches/sensors indicate that the position of piston is at or near theother end of the cylinder bore 338 (at the other end of the pumpingstroke). The switches/sensors may be used for calibration, or duringstepper motor operation to determine the piston position, or as notedherein for monitoring piston position during a diagnostic operation.

In one embodiment (described below) the stepper motor is energized byPWM pulses to drive the piston forward through a power stroke to aposition sensed by the forward sensor 442. The stepper motor is thenreversed and energized by PWM pulses to drive the piston in a rearwarddirection through a venting or non-venting return stroke. The length ofthe return stroke is determined by applying a preset number of PWMpulses to the stepper motor to move the piston rearward from its forwardposition as sensed by the forward sensor 442.

In another embodiment, the controller 450 includes an integral motordriver circuit and controls the operation of the stepper motor 394 bycontrolling the driver circuit to selectively apply PWM pulses to thestepper motor 394 to control a speed and a torque of the motor toreciprocate the piston. The controller is also responsive to one or morepressure sensors sensing lubricant pressure, such as the pressure sensor372 for sensing the pressure at the outlet of the cylinder bore. Thepressure sensor provides a pressure signal indicative of the sensedpressure of the lubricant supplied via the cylinder outlet. Thecontroller 450 is responsive to the pressure signal to selectively applythe PWM pulses to the stepper motor 394 to vary the speed and the torqueof the stepper motor as a function of the pressure signal by applyingPWM pulses having a power within a continuous duty operating range ofthe stepper motor. In some embodiments, the pressure sensor may be asensor for sensing the current of the motor 394 since motor current isindicative of pressure, so that the pressure signal may be a signalindicative of motor current.

The speed of the stepper motor 394 may controlled by the duty cycle ofPWM pulses applied to the motor to energize the motor. The torque of thestepper motor may controlled by the width (e.g., duration) of PWM pulsesapplied to the motor to energize the motor. Thus, the PWM pulses have avoltage (pulse height) and a current (pulse width) resulting in a powerlevel being applied to the motor. In general, the stepper motor may becontrolled by adjusting motor voltage, motor current, pulse duty cycle,and/or pulse power.

FIG. 56 is a graph illustrating an exemplary power curve 3000 (or motortemperature curve) over time of the stepper motor and furtherillustrating an exemplary continuous duty operating range 3001 of thestepper motor. When the motor is operating in this range 3001, internalheat is developed resulting in the motor temperature being at or below acritical temperature 3003. Frequently, the continuous duty operatingrange 3001 is based on various characteristics of a motor, such as itssize and materials. If a motor is operated within the continuous dutyoperating range 3001, its temperature stabilizes below the criticaltemperature 3003 so that the motor can be operated for extended periodsof time without and significant detrimental effects. However, if a motoris operated above the continuous duty operating range, its temperaturestabilizes above the critical temperature 3003 so that the motor can beoperated only for a limited period of time without and significantdetrimental effects. If a motor is operated above the continuous dutyoperating range and its temperature stabilizes above the criticaltemperature 3003, and if the motor is operated beyond the limited periodof time, significant detrimental effects may occur.

In FIG. 56, the power curve 3001 defines the approximate difference orboundary between operating the motor for a period of time withoutsignificant detrimental effects and operating the motor for a period oftime with significant detrimental effects. Operation of the motor at apower level and for a period of time which is within an area 3002 belowa dashed line 3004 is within the continuous duty operating range 3001and no significant detrimental damage occurs. The dashed line 3004 isgenerally referred to as the continuous duty rating of the motor.

Operating the motor at a power level and for a period of time which iswithin an area 3006 above the dashed line 3004 and to the left of thecurve 3000 (above and beyond the area 3002 of the continuous dutyoperating range 3001) does not cause significant detrimental damagebecause the period of time is relatively short and no excessive heatbuilds up in the motor. On the other hand, operating the motor at apower level and for an extended period of time which is within an area3008 above the dashed line 3004 and to the right of the power curve 3000(above and beyond the area 3002 of the continuous duty operating range3001) does cause significant detrimental damage because excessive heatbuilds up in the motor causing damage. In general, applying increasedpower to the stepper motor results in a corresponding increase in thetemperature of the motor. In some stepper motors, 80° C. is specified asthe maximum motor temperature rating. Thus, in such motors, operatingthe motor to the left of curve 3000 of FIG. 56 would be operating withinthe motor rating whereas operating the motor to the right of curve 3000of FIG. 56 would be operating outside the motor rating.

For example, operating the motor at a power level W1 and for a period oftime T1 to T2 within the area 3006 above the dashed line 3004 and to theleft of the curve 3001 as illustrated by line 3010 does not causesignificant detrimental damage to the stepper motor. This is because theperiod of time T1 to T2 is relatively short and no excessive heat buildsup in the motor. On the other hand, operating the motor at a power levelW2 and for the period of time T1 to T2 within the area 3008 above thedashed line 3004 and to the right of the curve 3001, as illustrated byline 3012, can cause significant detrimental damage to the steppermotor. This is because the period of time T1 to T2 is relatively long,crosses curve 3000 and excessive heat builds up in the motor which cancause damage. Operating the motor at a power level W3 and for a periodof time T1 to T3 within the area 3002 below the dashed line 3004, asillustrated by line 3014, does not cause significant detrimental damageto the stepper motor. Even though the period of time T1 to T3 isrelatively long, no excessive heat builds up within the stepper motorbecause the motor is operating within area 3002 representing thecontinuous duty operating range of the motor.

As noted above, the controller 450 is responsive to the pressure signalfrom the pump PT to selectively apply the pulse width modulated (PWM)pulses to the stepper motor 394 to vary the speed and the torque of thestepper motor as a function of the pressure signal by applying PWMpulses having a power within the continuous duty operating range of thestepper motor. For most if not all of the time of stepper motoroperation, the controller responds to the pressure signal to apply PWMpulses to the stepper motor having a power which falls within the area3002 of the continuous duty operating range of the stepper motor. Aspressure builds in the system, or if other factors impede the desiredpressure levels, it is contemplated that the controller responds to thepressure signal to apply PWM pulses to the stepper motor having a powerwhich falls within the overdrive area 3006 above dashed line 3004 andthe continuous duty operating range of the stepper motor and to the leftof curve 3001. Thus, the controller is responsive to the pressure signalto selectively apply the PWM pulses to the stepper motor to vary thespeed and torque of the stepper motor as a function of the pressuresignal by applying “overdrive” PWM pulses for a period of time. Theoverdrive PWM pulses have an overdrive power greater than the continuousduty operating range of the stepper motor. FIG. 57 illustrates one suchembodiment.

As shown in FIG. 57, the controller 450 includes a memory storing aspeed vs. pressure profile 3022 of the stepper motor 394. In thisembodiment, the controller is responsive to the pressure signal from thepump PT to selectively apply PWM pulses to the stepper motor to vary thespeed and the torque of the stepper motor as a function of the pressuresignal and as a function of the profile 3022 by applying PWM pulseshaving a power that is both inside and outside the continuous dutyoperating range of the stepper motor, as described below.

The profile 3022 includes three stages, a first stage 3024, a secondstage 3026 and a third stage 3028. During the first stage 3024, the PWMpulses drive the motor at about 1000 rpm between about zero and 1000psi. During the second stage 3026, the PWM pulses drive the steppermotor 394 at about 600 rpm between about 1000 and 2000 psi. During thethird stage 3028, the PWM pulses drive the motor at about 200 rpmbetween about 2000 and 3000 psi. Reference character 3030 illustratesthe stall curve of the stepper motor, also shown in FIG. 58. To the leftof (below) the stall curve 3030 is a motor operating area 3034 (FIG. 58)in which the motor operates at a speed and pressure without stalling,and to the right of (above) the stall curve 3030 is a motor stall area3036 in which the motor operates at a speed and pressure at which themotor tends to stall. When the speed of the motor at a particularpressure is to the left of the stall curve 3030, the motor hassufficient speed to push lubricant and maintain or increase the pressureof the lubricant. However, if the pressure at a particular speedincreases so that the motor is operating at or to the right of the stallcurve 3030, the motor has a tendency to stall. In other words, when thespeed of the motor at a particular pressure is to the right of the stallcurve 3030, the motor may have insufficient speed to push lubricant andthe motor tends to stall.

In one embodiment (FIG. 57), the latter part of each stage may includeoverdriving the stepper motor 394 for a period of time. For example,consider a stepper motor that is driven with pulse width modulated (PWM)pulses having a constant voltage, e.g., 24 volts, and having a varyingduration which falls within the continuous duty operating range, e.g.,0-5 amps. During the first stage 3024, the pulse width modulated (PWM)pulses would have durations between 0-5 amps to drive the motor at about1000 rpm between about zero and 900 psi. At about 900 psi, the motorwould have insufficient power (i.e., current or torque which isdetermined by the duration of the pulse) to increase the pressure to adesired target pressure of 1000 psi. At this point, the controller wouldcontrol the driver circuit to overdrive the motor for a period of time.This can be accomplished by increasing the current supplied to themotor, for a limited period of time, so that the PWM pulses would havedurations between 5-8 amps to provide sufficient power to drive themotor at about 1000 rpm between about 900 and 1000 psi.

During the second stage 3026, the PWM pulses would have durationsbetween 0-5 amps to drive the stepper motor 394 at about 600 rpm betweenabout 1000 and 1900 psi. At about 1900 psi, the motor would haveinsufficient power (i.e., current or torque which is determined by theduration of the pulse) to increase the pressure to a desired targetpressure of 2000 psi. At this point, the controller would control thedriver circuit to overdrive the motor for a period of time. This can beaccomplished by increasing the current supplied to the motor, for alimited period of time, so that the PWM pulses would have durationsbetween 5-8 amps to provide sufficient power to drive the motor at about600 rpm between about 1900 and 2000 psi.

During the third stage 3028, the PWM pulses would have durations between0-5 amps to drive the motor at about 200 rpm between about 2000 and 2900psi. At about 2900 psi, the stepper motor 394 would have insufficientpower (i.e., current or torque which is determined by the duration ofthe pulse) to increase the pressure to a desired target pressure of 3001psi. At this point, the controller would control the driver circuit tooverdrive the motor for a period of time. This can be accomplished byincreasing the current supplied to the motor, for a limited period oftime, so that the PWM pulses would have durations between 5-8 amps toprovide sufficient power to drive the motor at about 200 rpm betweenabout 2900 and 3001 psi.

It is also contemplated that the height of the PWM pulse, which is thevoltage of the PWM pulse, may be increased instead of increasing theduration (current) of the pulse in order to increase the power of thepulse and overdrive the stepper motor 394. It is also contemplated thatthe height of the PWM pulse, which is the voltage of the PWM pulse, maybe increased in addition to increasing the duration (current) of thepulse in order to increase the power of the pulse and overdrive themotor.

As a result, as illustrated in FIGS. 57 and 58, the controllerselectively applies the PWM pulses to the stepper motor to vary thespeed and torque of the stepper motor as a function of the pressuresignal from the pump PT by applying overdrive pulse width modulated(PWM) pulses for a period of time of overdrive operation. The period oftime may be fixed and/or it may vary based on another parameter. Forexample, as shown in FIG. 57, the stated period of time would be thetime required during the first stage 3024 to ramp up the pressure from900 psi to 1000 psi. Similarly, the stated period of time would be thetime required during the second stage 3026 to ramp up the pressure from1900 psi to 2000 psi. Similarly, the stated period of time would be thetime required during the third stage 3028 to ramp up the pressure from2900 psi to 3001 psi. During each stage, a maximum time for the statedperiod of time of overdrive operation could be set based on FIG. 56. Themaximum time for a given power would be set to avoid operating the motorin area 3008 since the overdrive PWM pulses have an overdrive powergreater than the continuous duty operating range of the motor.

In one embodiment described above, the stepper motor is operated in thearea 3006 (see W1, time T1 to T2) during an overdrive operation, andoperating the stepper motor in the area 3008 (see W2, time T1 to T2) isavoided, at least for any significant period of time. Thus, the periodof time of overdrive operation is a function of the overdrive powerrelative to the continuous duty operating range of the stepper motor. Inother words, the controller selectively applies the PWM pulses to thestepper motor to vary the speed and torque of the stepper motor as afunction of the pressure signal from the pump PT by applying overdrivePWM pulses for a period of time. The overdrive PWM pulses have anoverdrive power greater than the continuous duty operating range of thestepper motor, and the period of time is a function of the overdrivepower relative to the continuous duty operating range of the steppermotor. Thus, the controller applies pulse width modulated (PWM) pulsesto the stepper motor 394 such that the speed of the stepper motor is afirst speed (e.g., 1000 rpm) when the pressure signal from the pump PTis within a first range (1 to 1000 psi) defined by the first stage 3024.Similarly, the controller applies PWM pulses to the stepper motor suchthat the speed of the stepper motor is a second speed (e.g., 600 rpm)less than the first speed when the pressure signal from the pump PT iswithin a second range (e.g., 1000 psi to 2000 psi) defined by the secondstage 3026, the second range being higher than the first range.Similarly, the controller applies PWM pulses to the stepper motor suchthat the speed of the stepper motor is a third speed (e.g., 200 rpm)less than the second speed when the pressure signal from the pump PT iswithin a third range (e.g., 2000 psi to 3001 psi) defined by the thirdstage 3028, the third range being higher than the second range.

One perspective of the profile is that the controller determines thespeed of the stepper motor 394 based on a duty cycle of the pulsesapplied to the stepper motor. From this perspective, the controllerapplies overdrive PWM pulses to the stepper motor when the pressuresignal from the pump PT is within a preset range (e.g., 900 psi to 1000psi for the first stage 3024; 1900 psi to 2000 psi for the second stage3026; and 2900 psi to 3001 psi for the third stage 3028) and when thespeed of the motor is within a preset range. As noted above regardingFIG. 56, the overdrive PWM pulses have an overdrive power greater thanthe continuous duty operating range of the stepper motor.

In one embodiment, a temperature sensor is positioned adjacent thestepper motor 394 to monitor the temperature of the motor to maintainthe motor below its maximum motor temperature rating. The controllerreceives a signal from the temperature sensor indicative of the motortemperature. In this embodiment, the period of time for overdriving themotor is a function of the temperature of the stepper motor. Further,the motor may have a maximum temperature for a given speed, torque,current, power, pressure or rpm. The controller is configured to operatethe motor only within the continuous duty operating range of the steppermotor once the motor temperature sensor indicates that the motortemperature has reached its maximum temperature to inhibit motor damage.Alternatively, the controller is configured to discontinue operation ofthe motor once the motor temperature sensor indicates that the motortemperature has reached a certain temperature to inhibit motor damage.

In other embodiments, a temperature sensor may not be needed. It will benoted in this regard that the amount of power applied to a stepper motoris proportional to the increase of the temperature of the stepper motor.Thus, the temperature of the motor can be calculated by the processorbased on the power over time applied to the motor.

In one embodiment, the controller determines the speed of the steppermotor 394 based on a duty cycle of the pulses applied to the steppermotor. Alternatively, or in addition, the speed may be determined by amotor speed sensor, such as a Hall sensor, connected to the controllerand associated with a servo motor for driving the pump stepper motor.

In one embodiment, the speed/pressure profile stored in the memory ofthe controller is defined by at least one or more of an algorithm and alook-up table. For example, an algorithm for defining a speed/pressurecurve as illustrated by the dashed line 3032 of FIG. 57 may be stored inthe memory and executed by the controller.

The motor overdrive feature described above has been in the context oflubrication systems which include the pump unit 300 described earlier.However, it will be understood that these same overdrive features can beused in lubrication systems having other pump units, such as the pumpsunits 2500, 2900 described above and other pump units that include astepper motor or an alternative linear position drive mechanism (e.g.,the mechanism of FIG. 20 or FIG. 21).

As will be appreciated by those skilled in the art, features of each ofthe previously described embodiments may be combined with features ofother embodiments. These combinations are envisioned as being within thescope of the present invention.

Embodiments of the invention may be described in the general context ofdata and/or computer-executable instructions, such as program modules,stored one or more tangible computer storage media and executed by oneor more computers or other devices. Generally, program modules include,but are not limited to, routines, programs, objects, components, anddata structures that perform particular tasks or implement particularabstract data types. Aspects of the invention may also be practiced indistributed computing environments where tasks are performed by remoteprocessing devices that are linked through a communications network. Ina distributed computing environment, program modules may be located inboth local and remote computer storage media including memory storagedevices.

In operation, computers and/or servers may execute thecomputer-executable instructions such as those illustrated herein toimplement aspects of the invention.

Embodiments of the invention may be implemented with computer-executableinstructions. The computer-executable instructions may be organized intoone or more computer-executable components or modules on a tangiblecomputer readable storage medium. Aspects of the invention may beimplemented with any number and organization of such components ormodules. For example, aspects of the invention are not limited to thespecific computer-executable instructions or the specific components ormodules illustrated in the figures and described herein. Otherembodiments of the invention may include different computer-executableinstructions or components having more or less functionality thanillustrated and described herein.

The order of execution or performance of the operations in embodimentsof the invention illustrated and described herein is not essential,unless otherwise specified. That is, the operations may be performed inany order, unless otherwise specified, and embodiments of the inventionmay include additional or fewer operations than those disclosed herein.For example, it is contemplated that executing or performing aparticular operation before, contemporaneously with, or after anotheroperation is within the scope of aspects of the invention.

When introducing elements of aspects of the invention or the embodimentsthereof, the articles “a,” “an,” “the,” and “said” are intended to meanthat there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.

In view of the above, it will be seen that several advantages of theinvention are achieved and other advantageous results attained.

Not all of the depicted components illustrated or described may berequired. In addition, some implementations and embodiments may includeadditional components. Variations in the arrangement and type of thecomponents may be made without departing from the spirit or scope of theclaims as set forth herein. Additional, different or fewer componentsmay be provided and components may be combined. Alternatively or inaddition, a component may be implemented by several components.

The Abstract and Summary are provided to help the reader quicklyascertain the nature of the technical disclosure. They are submittedwith the understanding that they will not be used to interpret or limitthe scope or meaning of the claims.

The above description illustrates the invention by way of example andnot by way of limitation. When two items or multiple items areillustrated, it is contemplated that the invention may include two ormore items. This description enables one skilled in the art to make anduse the invention, and describes several embodiments, adaptations,variations, alternatives and uses of the invention, including what ispresently believed to be the best mode of carrying out the invention.Additionally, it is to be understood that the invention is not limitedin its application to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thedrawings. The invention is capable of other embodiments and of beingpracticed or carried out in various ways. Also, it will be understoodthat the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

Having described aspects of the invention in detail, it will be apparentthat modifications and variations are possible without departing fromthe scope of aspects of the invention as defined in the appended claims.As various changes could be made in the above constructions, products,and methods without departing from the scope of aspects of theinvention, it is intended that all matter contained in the abovedescription and shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

The invention claimed is:
 1. A system for supplying lubricant,comprising: a reservoir for holding lubricant, said reservoir having areservoir outlet; a pump comprising a cylinder defining a cylinder bore,a cylinder inlet in communication with said reservoir outlet for flow oflubricant from the reservoir into the cylinder bore, and a cylinderoutlet supplying lubricant, a piston movable in the cylinder bore; alubricant delivery system in communication with said cylinder outlet fordelivering lubricant; a drive mechanism including a stepper motor formoving the piston in the cylinder bore; a sensor for sensing a conditionof the system and providing a condition signal corresponding to thecondition; a controller for controlling the operation of the steppermotor by selectively energizing the stepper motor to move the piston,said controller responsive to the condition signal to modify operationof the stepper motor; and an alarm; wherein the sensor comprises apressure sensor monitoring a lubricant pressure of the lubricantdelivery system, wherein the condition signal is a pressure signal andwherein the controller is responsive to the pressure signal to energizethe alarm when the pressure signal indicates that the lubricant pressureis less than a minimum pressure after a given period of time ofoperating the stepper motor has elapsed; and said controller controllingpulses applied to the stepper motor, wherein the controller isresponsive to the condition signal to vary the speed and/or torque ofthe stepper motor depending on a value of the condition signal.
 2. Thesystem of claim 1, wherein the controller comprises a processor andfurther comprising a tangible, computer readable non-transitory storagemedium including processor executable instructions for controlling theoperation of the processor, wherein the processor executes theinstructions, and wherein the instructions comprise instructions forperforming a vent test to determine whether a lubricant injectorconnected to the system is venting based on the pressure signal providedby the pressure sensor and for energizing the alarm when the vent testindicates that the injector is not venting.
 3. The system of claim 2,further comprising an end-of-line pressure transducer for sensing anend-of-line lubricant pressure and for providing an end-of-line pressuretransducer reading corresponding to the end-of-line lubricant pressure,wherein the instructions for performing a vent test to determine whethera lubricant injector connected to the system is venting furthercomprise: determining whether the end-of-line pressure transducerreading corresponding to a lubricant pressure at the lubricant injectoris below a vent pressure setting; and, operating the pump stepper motorto perform a vent test in the event that the end-of-line pressuretransducer reading is not below a vent pressure setting.
 4. The systemof claim 3, wherein the instructions for performing a vent test todetermine whether a lubricant injector connected to the system isventing further comprise instructions for: determining a yield stressvalue of the lubricant based on the pressure signal; comparing thedetermined value to a preset level value; providing an indication ofpositive (passing) vent test results in the event that the determinedvalue is less than the preset level value; and, providing an indicationof negative (failing) vent test results in the event that the determinedvalue is greater than the preset level value.
 5. The system of claim 4,wherein the instructions for performing a vent test to determine whethera lubricant injector connected to the system is venting furthercomprise: providing an indication of a failure of the lubricant injectorto vent; and, stopping the stepper motor; wherein the instructions forenergizing the alarm further comprise instructions for activating thealarm after providing the indication of the vent test results.
 6. Thesystem of claim 5, further comprising a display, and wherein theinstructions for performing a vent test to determine whether a lubricantinjector connected to the system is venting further comprise:instructions for showing the provided positive (passing) vent testresults and the provided indication of a failure to vent in the eventthat the determined value is less than the preset level value; and,instructions for showing the provided negative (failing) vent testresults and the provided indication of a failure to vent in the eventthat the determined value is greater than the preset level value.
 7. Asystem for supplying lubricant, comprising: a reservoir for holdinglubricant, said reservoir having a reservoir outlet; a pump comprising acylinder defining a cylinder bore, a cylinder inlet in communicationwith said reservoir outlet for flow of lubricant from the reservoir intothe cylinder bore, and a cylinder outlet supplying lubricant, a pistonmovable in the cylinder bore; a lubricant delivery system incommunication with said cylinder outlet for delivering lubricant; adrive mechanism including a stepper motor for moving the piston in thecylinder bore; a sensor for sensing a condition of the system andproviding a condition signal; and, a controller for controlling theoperation of the stepper motor by selectively energizing the steppermotor to move the piston, said controller responsive to the conditionsignal to modify operation of the stepper motor; and an alarm; a stirrerin the reservoir and a stirrer motor driving the stirrer, saidcontroller selectively energizing the stirrer motor, wherein the sensorcomprises a current sensor monitoring a current applied to the stirrermotor, wherein the condition signal is a current signal and wherein thecontroller is responsive to the current signal to energize the alarmwhen the current signal indicates that the current applied to thestirrer motor is greater than a maximum current; and said controllercontrolling pulses applied to the stepper motor, wherein the controlleris responsive to the condition signal to vary the speed and/or torque ofthe stepper motor depending on a value of the condition signal.
 8. Thesystem of claim 7, further comprising a pressure sensor for sensing alubricant pressure of the lubricant delivery system and for providing apressure signal corresponding to the lubricant pressure, wherein thecontroller comprises a processor and further comprising a tangible,computer readable non-transitory storage medium including processorexecutable instructions for controlling the operation of the processor,wherein the processor executes the instructions, and wherein theinstructions comprise instructions for performing a vent test todetermine whether a lubricant injector connected to the system isventing based on the pressure signal provided by the pressure sensor andfor energizing the alarm when the vent test indicates that the injectoris not venting.
 9. The system of claim 8, further comprising anend-of-line pressure transducer for sensing an end-of-line lubricantpressure and for providing an end-of-line pressure transducer readingcorresponding to the end-of-line lubricant pressure, wherein theinstructions for performing a vent test to determine whether a lubricantinjector connected to the system is venting further compriseinstructions for: determining whether the end-of-line pressuretransducer reading corresponding to a lubricant pressure at thelubricant injector is below a vent pressure setting; and, operating thepump stepper motor to perform a vent test in the event that theend-of-line pressure transducer reading is not below a vent pressuresetting.
 10. The system of claim 9, wherein the instructions forperforming a vent test to determine whether a lubricant injectorconnected to the system is venting further comprise instructions for:determining a yield stress value of the lubricant based on the pressuresignal; comparing the determined value to a preset level value;providing an indication of positive (passing) vent test results in theevent that the determined value is less than the preset level value;and, providing an indication of negative (failing) vent test results inthe event that the determined value is greater than the preset levelvalue.
 11. The system of claim 10, wherein the instructions forperforming a vent test to determine whether a lubricant injectorconnected to the system is venting further comprise instructions for:providing an indication of a failure of the lubricant injector to vent;and, stopping the stepper motor; wherein the instructions for energizingthe alarm further comprise instructions for activating the alarm afterproviding the indication of the vent test results.
 12. The system ofclaim 11, further comprising a display, and wherein the instructions forperforming a vent test to determine whether a lubricant injectorconnected to the system is venting further comprise: instructions forshowing the provided positive (passing) vent test results and theprovided indication of a failure to vent in the event that thedetermined value is less than the preset level value; and, instructionsfor showing the provided negative (failing) vent test results and theprovided indication of a failure to vent in the event that thedetermined value is greater than the preset level value.
 13. A systemfor supplying lubricant, comprising: a reservoir for holding lubricant,said reservoir having a reservoir outlet; a pump comprising a cylinderdefining a cylinder bore, a cylinder inlet in communication with saidreservoir outlet for flow of lubricant from the reservoir into thecylinder bore, and a cylinder outlet supplying lubricant, a pistonmovable in the cylinder bore; a lubricant delivery system incommunication with said cylinder outlet for delivering lubricant; adrive mechanism including a stepper motor for moving the piston in thecylinder bore; a sensor for sensing a condition of the system andproviding a condition signal; and, a controller for controlling theoperation of the stepper motor by selectively energizing the steppermotor to move the piston, said controller responsive to the conditionsignal to modify operation of the stepper motor; and an alarm; whereinthe lubricant delivery system includes an injector and wherein thesensor is a pressure sensor configured for sensing a lubricant pressuresupplied to the injector and configured to provide a pressure signalcorresponding thereto and wherein the controller selectively energizesthe stepper motor in response to the pressure signal to activate theinjector to dispense lubricant; said controller controlling pulsesapplied to the stepper motor, wherein the controller is responsive tothe condition signal to vary the speed and/or torque of the steppermotor depending on a value of the condition signal.
 14. The system ofclaim 13, wherein the controller comprises a processor and furthercomprising a tangible, computer readable non-transitory storage mediumincluding processor executable instructions for controlling theoperation of the processor, wherein the processor executes theinstructions, and wherein the instructions comprise instructions forperforming a vent test to determine whether the lubricant injectorconnected to the system is venting based on the pressure signal providedby the pressure sensor and for energizing the alarm when the vent testindicates that the injector is not venting.
 15. The system of claim 14,wherein the instructions for performing a vent test to determine whetherthe lubricant injector connected to the system is venting furthercomprise instructions for: determining whether the lubricant pressuresupplied to the injector is below a vent pressure setting; and,operating the pump stepper motor to perform a vent test in the eventthat the lubricant pressure supplied to the injector is not below a ventpressure setting.
 16. The system of claim 15, further comprising apressure sensor for sensing a lubricant pressure generally at thecylinder outlet of the pump and for providing a pressure signalcorresponding to the lubricant pressure generally at the cylinderoutlet, wherein the instructions for performing a vent test to determinewhether the lubricant injector connected to the system is ventingfurther comprise instructions for: determining a yield stress value ofthe lubricant based on the pressure signal corresponding to thelubricant pressure generally at the cylinder outlet; comparing thedetermined value to a preset level value; providing an indication ofpositive (passing) vent test results in the event that the determinedvalue is less than the preset level value; and, providing an indicationof negative (failing) vent test results in the event that the determinedvalue is greater than the preset level value.
 17. The system of claim16, wherein the instructions for performing a vent test to determinewhether the lubricant injector connected to the system is ventingfurther comprise instructions for: providing an indication of a failureof the lubricant injector to vent; and, stopping the stepper motor;wherein the instructions for energizing the alarm further compriseinstructions for activating the alarm after providing the indication ofthe vent test results.
 18. The system of claim 17, further comprising adisplay, and wherein the instructions for performing a vent test todetermine whether the lubricant injector connected to the system isventing further comprise: instructions for showing the provided positive(passing) vent test results and the provided indication of a failure tovent in the event that the determined value is less than the presetlevel value; and, instructions for showing the provided negative(failing) vent test results and the provided indication of a failure tovent in the event that the determined value is greater than the presetlevel value.
 19. A method for supplying lubricant, comprising: providinga pump; providing a stepper motor which, when energized, actuates thepump to deliver lubricant from a reservoir to a lubricant injector;sensing a condition of the lubricant and providing a condition signal;and, controlling the operation of the stepper motor by selectivelyenergizing the stepper motor to actuate the pump in response to thecondition signal to selectively modify the operation of the steppermotor; wherein the sensing includes performing a vent test to determinewhether the lubricant injector is venting and energizing an alarm whenthe vent test indicates that the injector is not venting.
 20. A systemfor supplying lubricant, comprising: a pump; a stepper motor which, whenenergized, actuates the pump to deliver lubricant from a reservoir; asensor for sensing a condition of the lubricant and providing acondition signal; and, a controller for controlling the operation of thestepper motor by selectively energizing the stepper motor to actuate thepump in response to the condition signal to selectively modify theoperation of the stepper motor; wherein the controller is configured toperform a vent test to determine whether a lubricant injector is ventingand activate an alarm when the vent test indicates that the injector isnot venting.